0:00:05 > 0:00:09Something new is happening on planet Earth,
0:00:09 > 0:00:12big enough to be seen from space.
0:00:13 > 0:00:19Hot spots, buzzing with the energy of millions of people.
0:00:20 > 0:00:26For the first time in human history, more of us live in cities than in the country.
0:00:26 > 0:00:30But these are cities on a different scale.
0:00:30 > 0:00:35In just 50 years, we've seen the birth, the growth
0:00:35 > 0:00:40and now the dominance of the megacity.
0:00:43 > 0:00:47Sprawling, seething, noisy, polluted,
0:00:47 > 0:00:53crammed with 10 million, 15, sometimes even 30 million people.
0:00:53 > 0:00:58These cities are complicated, fragile places,
0:00:58 > 0:01:01constantly on the edge.
0:01:02 > 0:01:07These are places of overcrowded squalor.
0:01:08 > 0:01:13But these are also the most exciting places on the earth.
0:01:13 > 0:01:16Brim with optimism and fun and energy.
0:01:16 > 0:01:19Hey! HE GRUNTS
0:01:19 > 0:01:23Love them or loathe them, fear them or embrace them,
0:01:23 > 0:01:29the megacities are the human future of the planet.
0:01:31 > 0:01:33We have, at the last count,
0:01:33 > 0:01:37created 21 of these extraordinary urban sprawls.
0:01:37 > 0:01:43Pulsing and beating entities, giant organisms in their own right.
0:01:43 > 0:01:47And these cities and our experience of them
0:01:47 > 0:01:50is shaped by how we move around them.
0:01:50 > 0:01:53Total chaos! I would call it anarchy,
0:01:53 > 0:01:56but that would be extremely unfair on anarchists.
0:01:56 > 0:02:00In this film, I'm going to be asking how our megacities can survive
0:02:00 > 0:02:03without having a colossal heart attack.
0:02:03 > 0:02:07Motorways, the freeways, the railways below us
0:02:07 > 0:02:10are the veins and the arteries.
0:02:10 > 0:02:15But all round the world, these arteries are getting clogged up and congested.
0:02:15 > 0:02:19They're gobbling ever more resources...
0:02:19 > 0:02:21That's some cow!
0:02:21 > 0:02:26..and dumping grotesque amounts of waste.
0:02:26 > 0:02:31So, how does the metropolis deal with all the stuff its people don't want?
0:02:31 > 0:02:34Solid fat!
0:02:34 > 0:02:38Now I want to wipe my nose but, on the whole, I think I won't.
0:02:38 > 0:02:40And what length do people go to
0:02:40 > 0:02:44to stop the modern metropolis from drowning in its own excess?
0:02:44 > 0:02:48It's unimaginable, what he's just lowered himself into.
0:03:03 > 0:03:07Why are our great cities where they are
0:03:07 > 0:03:11and why are they the shape they are?
0:03:11 > 0:03:12All around the world,
0:03:12 > 0:03:15you see the same pattern.
0:03:15 > 0:03:18Coastlines and river mouths.
0:03:18 > 0:03:19And there's no mystery
0:03:19 > 0:03:24in why the great cities love to dangle their feet in the water.
0:03:24 > 0:03:26Because throughout history,
0:03:26 > 0:03:31sea lanes and rivers were the original superhighways
0:03:31 > 0:03:38and even today, it's transport - that basic need to get in and out -
0:03:38 > 0:03:41that shapes and stretches
0:03:41 > 0:03:46and sometimes even strangles the cities of the world.
0:04:00 > 0:04:04How to move millions of people around a megacity 24 hours a day,
0:04:04 > 0:04:07without bringing the place to a shuddering halt
0:04:07 > 0:04:10and without literally choking its citizens to death,
0:04:10 > 0:04:15is one of the major challenges we will face in the 21st century.
0:04:18 > 0:04:21I'm starting this journey in one of the poorest,
0:04:21 > 0:04:24most chaotic and overcrowded cities of them all -
0:04:24 > 0:04:28Dhaka in Bangladesh.
0:04:29 > 0:04:34There's simply no money for fancy subways or slick freeways here.
0:04:34 > 0:04:37And with a population of 13 million, and rising, to shunt around,
0:04:37 > 0:04:41Dhaka is feeling the squeeze.
0:04:44 > 0:04:49People still have to move around. Whatever it takes.
0:04:49 > 0:04:53And it's hot, intense and rather dangerous.
0:04:55 > 0:05:00Every great city depends entirely on its transport system.
0:05:00 > 0:05:05But if there's one choke point all round the world, it's the morning rush hour,
0:05:05 > 0:05:08when millions upon millions of people
0:05:08 > 0:05:10struggle to get to their jobs
0:05:10 > 0:05:14and, seemingly, will do almost anything to make it in.
0:05:16 > 0:05:21The megacities are the most extreme example of this,
0:05:21 > 0:05:25and the poorer ones the most extreme of the extreme.
0:05:29 > 0:05:33There are so many people trying to move around this dense city
0:05:33 > 0:05:38that it feels like there isn't a rush hour, because the entire day is one massive rush hour.
0:05:38 > 0:05:39A rush day.
0:05:39 > 0:05:44With just two train lines to serve a population the same size as London's,
0:05:44 > 0:05:46and only one major highway,
0:05:46 > 0:05:49the result is predictable mayhem.
0:05:51 > 0:05:56So, how can you get around a city of 13 million people effectively?
0:05:56 > 0:06:01Actually, it's using one of the most primitive modes of modern transport,
0:06:01 > 0:06:03pedal power.
0:06:03 > 0:06:07Because Dhaka is the rickshaw capital of the world.
0:06:07 > 0:06:11Noisy, stinking, slow
0:06:11 > 0:06:14and extremely dangerous.
0:06:14 > 0:06:16CAR HORNS BEEP
0:06:16 > 0:06:19But for most people around the world
0:06:19 > 0:06:23this is the reality of urban transport,
0:06:23 > 0:06:26not some dinky high-speed train.
0:06:29 > 0:06:33There are well over half a million rickshaws in downtown Dhaka,
0:06:33 > 0:06:36that's roughly one for every 20 people.
0:06:36 > 0:06:41Hardly surprising, then, that 80 percent of all male newcomers to Dhaka
0:06:41 > 0:06:44start out as one of these human taxis.
0:06:44 > 0:06:48They work ten hours a day, seven days a week,
0:06:48 > 0:06:51pulling some seriously heavy loads.
0:06:51 > 0:06:57And so, as a new arrival, I think it only right I should have a go.
0:06:57 > 0:07:02Now, I'm a keen cyclist in London, so how hard can this really be?
0:07:02 > 0:07:05MAN SPEAKS BENGALI
0:07:05 > 0:07:10- TRANSLATION:- It isn't the traffic. He's saying it's difficult to ride in a...
0:07:10 > 0:07:12- Straight line?- Yeah.- Yeah.
0:07:12 > 0:07:15What are the most important rules of the street?
0:07:15 > 0:07:18TRANSLATOR SPEAKS BENGALI
0:07:20 > 0:07:24- The brake is the most important thing.- The brake's the most important thing, OK.
0:07:24 > 0:07:27Is it as easy as riding a bike?
0:07:27 > 0:07:30THEY CHATTER IN BENGALI
0:07:37 > 0:07:40I think that means it's not as easy as riding a bike!
0:07:41 > 0:07:43Here I go.
0:07:47 > 0:07:49HE LAUGHS
0:07:49 > 0:07:53Hey! HE GRUNTS
0:07:55 > 0:07:57CHILDREN CHEER
0:08:02 > 0:08:07Apparently, there are 600,000 of these in the city.
0:08:08 > 0:08:11And I'm beginning to get a sense
0:08:11 > 0:08:13of how much human horsepower
0:08:13 > 0:08:16it takes to move Dhaka around.
0:08:31 > 0:08:35I'm supposed to keep to the left, but it's so crowded here
0:08:35 > 0:08:38I'm being forced into the middle of the road.
0:08:38 > 0:08:43And with a cab on the back, it's difficult to judge exactly how tight a gap I can squeeze through.
0:08:44 > 0:08:47Oh, my God! Oh, I'm sorry.
0:08:47 > 0:08:48Oh, I'm sorry.
0:08:48 > 0:08:52What you soon realise is, you can never get up a good head of steam.
0:08:52 > 0:08:56You're constantly stopping and starting.
0:08:56 > 0:09:00And it's far harder and much more exhausting than it looks.
0:09:01 > 0:09:06That was both great fun and really, really hard work.
0:09:06 > 0:09:09More difficult than it seems.
0:09:09 > 0:09:13I had a great time doing it for about 20 minutes, but I think that's about my lot.
0:09:13 > 0:09:18These guys do it for, what, ten hours at a time or more?
0:09:18 > 0:09:19It's astonishing.
0:09:19 > 0:09:22They're said to be as fit as Olympic athletes
0:09:22 > 0:09:25and I have to say, I can well believe it.
0:09:25 > 0:09:29Thank you. OK. Thanks, guys.
0:09:30 > 0:09:32But Dhaka's reliance on rickshaws
0:09:32 > 0:09:35means more than simply back-breaking labour
0:09:35 > 0:09:37for tens of thousands of its citizens.
0:09:37 > 0:09:40It also affects the shape of the city.
0:09:40 > 0:09:44Because if your only means of getting around is by rickshaw,
0:09:44 > 0:09:48then you are restricted to travelling fairly short distances.
0:09:48 > 0:09:50Which means, in turn,
0:09:50 > 0:09:55that Dhaka is one of the most densely-populated metropolises in the world.
0:09:56 > 0:10:01If you look at the map of any old city and see how it grows,
0:10:01 > 0:10:07you can see that it expands in concentric rings as the transport gets better.
0:10:07 > 0:10:09From horses to bicycles,
0:10:09 > 0:10:13to cars and trams and trains and metro,
0:10:13 > 0:10:16the bigger the rings, the more effective the transport.
0:10:16 > 0:10:20There's one very simple truth...
0:10:21 > 0:10:25The better the transport, the bigger the city can grow.
0:10:25 > 0:10:29And today's megacities have taken that simple truth
0:10:29 > 0:10:33and pushed it to the absolute extreme.
0:10:35 > 0:10:39London. One of the planet's first great metropolises.
0:10:39 > 0:10:43With a population of 13 million, including all its surrounding areas,
0:10:43 > 0:10:48this city was built not on roads but on steel.
0:10:48 > 0:10:50In the early 19th Century,
0:10:50 > 0:10:55London was 30 times smaller than it is today.
0:10:55 > 0:11:00With only horsepower to move its people around, it simply couldn't get any bigger.
0:11:00 > 0:11:05And then a revolutionary new form of transport started to reshape this great metropolis
0:11:05 > 0:11:08and all of Britain's other big cities.
0:11:09 > 0:11:14The oldest megacities, like London, were only ever able to gobble up the land around them
0:11:14 > 0:11:18thanks to whizzy new technologies like the train.
0:11:18 > 0:11:23As the tendrils of train and tram networks spread out from the centre,
0:11:23 > 0:11:26the suburbs followed and the population mushroomed.
0:11:26 > 0:11:30And just when it looked as if the train companies couldn't demolish any more houses
0:11:30 > 0:11:32to build any more lines,
0:11:32 > 0:11:38they had another bright idea - to go under the houses instead.
0:11:40 > 0:11:44From the opening of the first underground station in 1863,
0:11:44 > 0:11:50in just 40 years, the population trebled to six million.
0:11:50 > 0:11:54London's roots would become criss-crossed by a web of tunnels,
0:11:54 > 0:11:58transporting more than 2.5 million people every day.
0:12:00 > 0:12:03It was revolutionary.
0:12:03 > 0:12:06And in the 150 years or so since then,
0:12:06 > 0:12:09the London Underground has hugely expanded
0:12:09 > 0:12:12and been rebuilt and patched up and grown and copied.
0:12:12 > 0:12:16But everything has its limits.
0:12:16 > 0:12:20The number of people you can squeeze through these tubes
0:12:20 > 0:12:24has now reached its maximum.
0:12:25 > 0:12:31It's a bit as if you were given one pair of trousers for life
0:12:31 > 0:12:33at the age of 12.
0:12:33 > 0:12:36You get bigger and bigger
0:12:36 > 0:12:40and, first of all, the trousers start to squeeze a little bit
0:12:40 > 0:12:44and then it's a really painful squeeze.
0:12:44 > 0:12:49Well, this wonderful piece of world-breaking technology
0:12:49 > 0:12:54has now become London's painful squeeze.
0:12:58 > 0:13:01That is the problem with these arteries of megacities.
0:13:01 > 0:13:04Very easily, they become crammed and sclerotic
0:13:04 > 0:13:07and they're on the edge of collapse again.
0:13:07 > 0:13:11The men who built the London Underground thought they had their city sorted.
0:13:11 > 0:13:13Nothing lasts forever.
0:13:13 > 0:13:16Success sucks in many more people
0:13:16 > 0:13:19until it starts to feel like failure.
0:13:19 > 0:13:23That doesn't stop people on the other side of the world trying just the same thing,
0:13:23 > 0:13:27though bigger and faster than London.
0:13:30 > 0:13:34This is the Shanghai Metro.
0:13:34 > 0:13:3820 years ago, Shanghai didn't have an underground at all.
0:13:38 > 0:13:41Now it boasts the largest one in the world,
0:13:41 > 0:13:44and they've built it at an awesome speed.
0:13:49 > 0:13:53- TRANSLATION:- The total soil excavated after completion of the networks
0:13:53 > 0:13:55will be around 22 million tonnes,
0:13:55 > 0:13:59including all the soil that needs to be dug out of the stations.
0:13:59 > 0:14:0222 million tonnes!
0:14:06 > 0:14:08I'm very proud of what we've done.
0:14:08 > 0:14:12In the last few years, we've managed to complete the same length of lines
0:14:12 > 0:14:15that it's taken 100 years for foreigners to build.
0:14:15 > 0:14:18It's a great method of transport.
0:14:22 > 0:14:26I'm sure London's engineers were just as confident all that time ago.
0:14:26 > 0:14:29But the Chinese Government haven't stopped with a mere subway.
0:14:29 > 0:14:32They've spent well over a billion pounds
0:14:32 > 0:14:35on a revolutionary new overground train system
0:14:35 > 0:14:37known as the Maglev.
0:14:37 > 0:14:40These trains, built in Germany, have no wheels.
0:14:40 > 0:14:43Using magnetic levitation,
0:14:43 > 0:14:48they literally float along the track at extraordinary speeds.
0:14:48 > 0:14:52We're doing 380 kilometres an hour.
0:14:52 > 0:14:56385. 388. 390.
0:14:56 > 0:14:58400 kilometres an hour.
0:15:00 > 0:15:02425, six, seven.
0:15:02 > 0:15:07431. We're now doing more than 431 kilometres an hour.
0:15:07 > 0:15:10I think that's about 270 miles an hour.
0:15:10 > 0:15:13This thing is flying.
0:15:13 > 0:15:18It makes a British InterCity train look like a horse and cart.
0:15:22 > 0:15:25And just as the tubes reshaped London,
0:15:25 > 0:15:28it's thought that these super-fast services
0:15:28 > 0:15:32will reshape this entire area of China.
0:15:36 > 0:15:39It's too soon to say
0:15:39 > 0:15:43how Maglev trains might reshape China,
0:15:43 > 0:15:49but experts are already talking about giant urban areas
0:15:49 > 0:15:54of perhaps 100 million people each.
0:15:54 > 0:15:57This is how futuristic transport
0:15:57 > 0:16:03can entirely reshape the way we think now about cities.
0:16:06 > 0:16:10Then again, I'm not so sure.
0:16:10 > 0:16:12People's dreams of futuristic freedom
0:16:12 > 0:16:15rarely pan out the way that's expected,
0:16:15 > 0:16:17and there's no clearer example of that
0:16:17 > 0:16:22than what's become the true curse of the megacity the world over -
0:16:22 > 0:16:24the humble car.
0:16:25 > 0:16:29And the people of Shanghai are in love with that.
0:16:30 > 0:16:36In China, just 25 years ago, private cars were banned.
0:16:36 > 0:16:40Now they're joining the roads of Shanghai alone
0:16:40 > 0:16:43at the rate of 1,000 every day.
0:16:43 > 0:16:48And China has become the largest car market in the world.
0:16:55 > 0:16:59Meet Shanghai citizens, Wenbing Wu and his wife Jee Chen.
0:17:00 > 0:17:06They've come to the BYD, or Build Your Dream, car showroom in Shanghai
0:17:06 > 0:17:09to take a look at a new motor.
0:17:09 > 0:17:14This would be the first vehicle that they, or any of their family, have ever owned.
0:17:14 > 0:17:20As far as I'm concerned, they have no idea of what they're letting themselves in for.
0:17:21 > 0:17:26- TRANSLATION:- We had to save every month. We've been saving up for a really long time.
0:17:27 > 0:17:31Wenbing and Jee are typical of the megacity-dwelling Chinese.
0:17:31 > 0:17:36The thing about cars, is that they are just so appealing.
0:17:36 > 0:17:39Who would want to sit on a sweaty subway
0:17:39 > 0:17:44or cram into a crowded bus when you can cruise in air-conditioned comfort?
0:17:44 > 0:17:47For many of us, commuting by public transport
0:17:47 > 0:17:50is such a gruelling experience
0:17:50 > 0:17:53that getting a private car is a tempting alternative.
0:17:53 > 0:17:56But this is about more than just getting from A to B.
0:17:56 > 0:17:59It's about status.
0:17:59 > 0:18:01Now, in a place like Shanghai,
0:18:01 > 0:18:07having a shiny new car of your own shows that you have made it.
0:18:07 > 0:18:10For this couple, it's clearly cost them a lot,
0:18:10 > 0:18:15but they seem convinced that their new car's going to be worth it.
0:18:16 > 0:18:20Now we've managed to get a car, all of my family are really happy about it.
0:18:20 > 0:18:25It's like you've realised what you've been dreaming about for so long.
0:18:25 > 0:18:29So all of us are really happy.
0:18:31 > 0:18:36If only we could take them by the hand and lead them to the streets of...
0:18:36 > 0:18:39Mexico City, say.
0:18:43 > 0:18:48For this really is a city built on tarmac.
0:18:48 > 0:18:50Here there are almost 20 million people
0:18:50 > 0:18:53and nearly five million cars.
0:18:56 > 0:18:58Traffic here is so heavy
0:18:58 > 0:19:05that commuters can spend six hours a day, a third of their waking lives,
0:19:05 > 0:19:07sitting in their cars
0:19:07 > 0:19:09just trying to get to work.
0:19:09 > 0:19:12This is transport not just shaping the megacity,
0:19:12 > 0:19:15it's in danger of killing it.
0:19:22 > 0:19:26The motorways, the freeways, the railways below us
0:19:26 > 0:19:31are the veins and the arteries of any city.
0:19:31 > 0:19:35We're in Mexico City, one of the most congested places on the planet.
0:19:35 > 0:19:39These arteries are getting clogged up and congested.
0:19:39 > 0:19:44And we know what happens if you get too much of that.
0:19:44 > 0:19:46You get an urban heart attack.
0:19:48 > 0:19:53Mexico City's traffic cops are fighting a war, and they are not winning.
0:19:59 > 0:20:03I'm with the police helicopter pilot Captain Oscar Cardenta
0:20:03 > 0:20:06to get a whirlybird's-eye-view of the morning commute.
0:20:09 > 0:20:13Just 7:30am. Already jams are forming down below,
0:20:13 > 0:20:16and they stretch as far as we can see.
0:20:18 > 0:20:22Right now, we're going to be coming up on, uh,
0:20:22 > 0:20:26on Periferico, which is usually very busy at this time of day.
0:20:26 > 0:20:29Mexico City's Periferico is the city's major ring road.
0:20:29 > 0:20:34If anything goes wrong here, the police know it will spawn rush-hour hell.
0:20:35 > 0:20:39- How can you help from the air? - I have a traffic specialist
0:20:39 > 0:20:42and he's giving orders to the people on the ground
0:20:42 > 0:20:46to detour the traffic, control the flow.
0:20:46 > 0:20:48It isn't long before Oscar spots trouble.
0:20:48 > 0:20:52Something's slowing down the traffic on a critical flyover.
0:20:52 > 0:20:55Left unchecked, this could spell gridlock, so he's straight onto it
0:20:55 > 0:21:00and a team of motorbike traffic police are despatched.
0:21:02 > 0:21:04They're going to need to act quickly
0:21:04 > 0:21:07because any hold-ups can degenerate into city-wide chaos.
0:21:09 > 0:21:12This time, it just turns out to be a broken-down car.
0:21:12 > 0:21:16The young couple driving it have simply run out of petrol.
0:21:20 > 0:21:22No hanging around for the AA here.
0:21:22 > 0:21:26So dire is the congestion, that in Mexico City
0:21:26 > 0:21:29the police have learned to improvise.
0:21:34 > 0:21:38Unconventional, but it works.
0:21:41 > 0:21:46So if we're all going to live in the megacity, and it rather looks like most of us will,
0:21:46 > 0:21:53are we all condemned to a future of choking jams and sweat-packed tube trains?
0:21:53 > 0:21:58No, I think that maybe we don't want to turn our backs on our low-tech past.
0:21:58 > 0:22:04Maybe Dhaka and its half a million cycle rickshaws
0:22:04 > 0:22:06does have something to teach us.
0:22:08 > 0:22:10Across the globe
0:22:10 > 0:22:14and London is gearing up for a three-speed revolution.
0:22:19 > 0:22:22To get real change in the city, you need two things.
0:22:22 > 0:22:26You need pent-up demand on the streets and you need proper leadership.
0:22:26 > 0:22:30When the two come together, change can happen very, very fast.
0:22:30 > 0:22:33A good example would be the London bicycle scheme.
0:22:35 > 0:22:38When this got going...
0:22:39 > 0:22:41..a lot of people said, "It's not going to work,"
0:22:41 > 0:22:45and within the first ten weeks there were a million journeys made.
0:22:45 > 0:22:49# I seen you riding around The streets at night
0:22:49 > 0:22:52# On your bicycle #
0:22:52 > 0:22:57There's no single magic bullet that's going to solve the megacity transport crisis.
0:22:57 > 0:23:01We have to snaffle ideas from all over the place,
0:23:01 > 0:23:03taking smaller, smarter solutions
0:23:03 > 0:23:06which, when you take them together, can have an impact.
0:23:06 > 0:23:09London's first large-scale public bike-hire scheme
0:23:09 > 0:23:14is part of that potential mix.
0:23:17 > 0:23:21In the economy of the great cities,
0:23:21 > 0:23:25they're always learning and copying and stealing from each other.
0:23:25 > 0:23:28And it's not just from the hi-tech cities.
0:23:28 > 0:23:31So Dhaka in Bangladesh may be a nightmare,
0:23:31 > 0:23:35but it's a nightmare run on pedal power
0:23:35 > 0:23:38and that's something that modern cities are re-learning.
0:23:38 > 0:23:43And so to have a transport system that really works you need everything.
0:23:43 > 0:23:48You need the taxis and the cars and the buses.
0:23:48 > 0:23:52You need the trains and you need bicycles
0:23:52 > 0:23:57and, of course, decent places to be able to walk safely, as well.
0:23:57 > 0:24:02It's a bit like fusion food, you know, that we eat all the time.
0:24:02 > 0:24:08You bring in all sorts of lessons, all sorts of flavours
0:24:08 > 0:24:09and you mix them up
0:24:09 > 0:24:12and with a bit of luck and leadership,
0:24:12 > 0:24:15you get a city that's moving again.
0:24:19 > 0:24:24This is an example of how the megacity can function at its best.
0:24:24 > 0:24:27A bit of technological innovation, some risk,
0:24:27 > 0:24:32fingers crossed, and openness to what's worked elsewhere.
0:24:32 > 0:24:34And what goes for transport
0:24:34 > 0:24:36goes for what is transported, as well.
0:24:36 > 0:24:38And not just people.
0:24:39 > 0:24:42Moving all of those commuters around,
0:24:42 > 0:24:46that's just one layer of the amazing web of activity.
0:24:46 > 0:24:49Because these people need to be clothed and fed
0:24:49 > 0:24:52and kept warm and watered,
0:24:52 > 0:24:56and that means that the megacity's routes
0:24:56 > 0:25:01stretch far beyond the ordinary city boundaries,
0:25:01 > 0:25:04to far-off generators providing the electricity
0:25:04 > 0:25:09or distant mountain reservoirs providing the piped water.
0:25:09 > 0:25:14But the greatest appetite is, of course, for food.
0:25:14 > 0:25:17The megacities are monstrous hungry.
0:25:21 > 0:25:2424 hours a day, seven days a week,
0:25:24 > 0:25:27they suck in an astonishing array of food.
0:25:27 > 0:25:30Flown, shipped and driven in from all round the world,
0:25:30 > 0:25:35and we expect it served how, when and where we want it.
0:25:46 > 0:25:51London is no exception. It's one very hungry and thirsty megacity.
0:25:51 > 0:25:55Every year, London eats seven million tonnes of food
0:25:55 > 0:26:00and downs 94 million litres of bottled water alone.
0:26:00 > 0:26:06London's total food footprint is 125 times its size.
0:26:06 > 0:26:12In other words, it requires the equivalent of the entire productive land of mainland Britain
0:26:12 > 0:26:14to feed London.
0:26:22 > 0:26:26Such is the megacity's demand for fresh food,
0:26:26 > 0:26:30we're forced to grow it on an increasingly industrial scale.
0:26:30 > 0:26:35Even the humble lettuce gets the treatment.
0:26:36 > 0:26:41This farm produces over 60 million lettuces every year.
0:26:41 > 0:26:47And to do that, it takes a well-drilled small army of pickers.
0:26:48 > 0:26:52Plants get lifted, and then creeping just behind is a machine
0:26:52 > 0:26:56with yet more workers bagging and packing.
0:26:57 > 0:27:02Within another 24 to 48 hours, they'll have been whisked down a motorway,
0:27:02 > 0:27:05unloaded, sorted, packed, loaded up again,
0:27:05 > 0:27:08and now they're in your fridge perhaps.
0:27:08 > 0:27:14Or they might end up here, in one of the strangest supermarkets I've ever been to.
0:27:17 > 0:27:21It is supersized.
0:27:22 > 0:27:27It looks like an ordinary supermarket, but it plainly isn't.
0:27:27 > 0:27:30The aisles are too big, the trolleys in those aisles are too big
0:27:30 > 0:27:34and the people doing the picking are all dressed in uniforms.
0:27:34 > 0:27:38Because the food that they're choosing, they're not going to take home and eat.
0:27:38 > 0:27:42They're not going to wash with the shampoo that they're selecting
0:27:42 > 0:27:45or drink the drinks they're taking off the shelves.
0:27:45 > 0:27:48They are buying for online shoppers
0:27:48 > 0:27:53and they're being told what to pick and how to pick it by a computer.
0:27:57 > 0:28:02So right now, to help feed the megacity, welcome to the mega supermarket.
0:28:03 > 0:28:06The shelves of this unique London Tesco online store
0:28:06 > 0:28:09groan with 22,500 items,
0:28:09 > 0:28:13spread over the equivalent of three football pitches.
0:28:15 > 0:28:19There are no bright and shiny signs enticing you to buy here,
0:28:19 > 0:28:24just series of numbers and codes guiding the pickers.
0:28:26 > 0:28:29When we pick, we have to pick by location.
0:28:29 > 0:28:33- OK.- So pick by location first...
0:28:33 > 0:28:36- It's the numbers of the aisles you're looking for?- Yes.
0:28:36 > 0:28:40- So you're looking for 61.- Yeah. - D2.- Right.
0:28:40 > 0:28:44Almond milk. Almond?
0:28:44 > 0:28:46- That's the one.- That's the one. - That's the one.
0:28:49 > 0:28:55Sharon and her fellow workers end up picking a total of 1,800 orders every day.
0:28:55 > 0:28:58That's like shopping 600,000 times for groceries a year.
0:28:58 > 0:29:01Quite a lot, it's a battle with the clock
0:29:01 > 0:29:05to juggle up to six separate customer orders at one go.
0:29:05 > 0:29:08They've all booked their delivery slots.
0:29:08 > 0:29:13And how quick do you have to be normally, when you're not surrounded by people like me?
0:29:13 > 0:29:17Erm, we've got a time bar at the bottom
0:29:17 > 0:29:21that tells us how quickly we're going.
0:29:21 > 0:29:26- At the moment, it's red and... - You're not going fast enough?- No.
0:29:26 > 0:29:28I'm well out of time.
0:29:28 > 0:29:32So they're possibly waiting for me, but...
0:29:32 > 0:29:35- So there's a specific van waiting for you?- Yeah.
0:29:36 > 0:29:42Being ordered around by a computer might make this a seemingly alienating job,
0:29:42 > 0:29:46but I'm reassured there is a personal touch, however small.
0:29:46 > 0:29:49So, what happens if you get to your number
0:29:49 > 0:29:53and what they want isn't there?
0:29:53 > 0:29:55We have to put a substitution in.
0:29:55 > 0:29:59I mean, like, I've substituted this morning, erm, red wine.
0:29:59 > 0:30:05- They wanted Cabernet Sauvignon. - Yeah.- I substituted it with Shiraz.
0:30:05 > 0:30:08- Right.- Shiraz is better anyway!
0:30:11 > 0:30:15The megacity says, "Make it bigger, do it faster."
0:30:15 > 0:30:17These people are presumably shopping online
0:30:17 > 0:30:20because their own lives are so stressed and under the cosh,
0:30:20 > 0:30:23they haven't got time to shop for themselves.
0:30:23 > 0:30:26The result is that they produce a whole other group of people
0:30:26 > 0:30:30who are also rushing around, shopping against the clock.
0:30:30 > 0:30:34But it's a curious business. What you choose to put in your mouth
0:30:34 > 0:30:37or put down your throat or clean yourself with,
0:30:37 > 0:30:39these are intimate decisions
0:30:39 > 0:30:43and we rely if not on the kindness of strangers
0:30:43 > 0:30:46then the choice of strangers.
0:30:46 > 0:30:50The honesty of strangers. The hard work of strangers.
0:30:55 > 0:30:58Of course, all this consumption inevitably has a consequence.
0:30:58 > 0:31:04Our modern megacities spew out huge quantities of waste.
0:31:04 > 0:31:08Every year, London throws away 20 million tonnes of the stuff.
0:31:08 > 0:31:11Trying to cope with just some of the deluge
0:31:11 > 0:31:13is causing a massive strain for megacities.
0:31:13 > 0:31:17An astonishing 40,000 miles of sewers
0:31:17 > 0:31:20lurk beneath Greater London.
0:31:20 > 0:31:22Uncoiled and laid end-to-end,
0:31:22 > 0:31:26they'd stretch twice around the world.
0:31:26 > 0:31:31But the original sewer system, a Victorian labyrinth of 450 miles of interconnecting tunnels,
0:31:31 > 0:31:33still serves the city above.
0:31:33 > 0:31:38And just like that other Victorian innovation, the London Underground,
0:31:38 > 0:31:41the sewers are struggling to cope.
0:31:41 > 0:31:45The arteries of the megacity are clogging up.
0:31:46 > 0:31:51I came into television to start with because I was looking for glamour.
0:31:53 > 0:31:55- HE LAUGHS - Now you've got it!
0:31:55 > 0:31:59'Rob Smith's one of 39 flushers
0:31:59 > 0:32:04'who maintain Central London's sewer network, and they do it the old-fashioned way - by hand.'
0:32:04 > 0:32:08- Are you ready to go then? - Ready to go.- Come this way.
0:32:09 > 0:32:12Here we go.
0:32:13 > 0:32:15Here it is.
0:32:16 > 0:32:23It smells exactly as you expect. I don't have to describe it.
0:32:23 > 0:32:29The Victorian sewer system was built when London was a mere toddler of a megacity,
0:32:29 > 0:32:31home to only 2.5 million people.
0:32:31 > 0:32:37150 years later, it has to deal with the end product of at least ten million.
0:32:37 > 0:32:40The biggest headache for Rob and the small army of flushers
0:32:40 > 0:32:43is not just what all those millions eat,
0:32:43 > 0:32:45but what it's cooked in, too.
0:32:48 > 0:32:49Wow.
0:32:49 > 0:32:51HE CHUCKLES
0:32:51 > 0:32:55- Yeah.- So, that's fat?- That's fat.
0:32:55 > 0:32:57Where does it come from?
0:32:58 > 0:33:01About a couple of miles up in that direction.
0:33:01 > 0:33:03We've got Leicester Square, Trafalgar Square.
0:33:03 > 0:33:09So, is this fat from restaurants and kebab shops and so on?
0:33:09 > 0:33:12Exactly. Yeah. Yeah, that's where it comes from.
0:33:12 > 0:33:16So when we talk about, you know, you eat too much fat, too many burgers and chips,
0:33:16 > 0:33:20- your arteries get furred up... - Same with the sewers.
0:33:20 > 0:33:24- This is London's arteries getting furred up with fat.- That's right.
0:33:24 > 0:33:29It's astonishing and very, very disgusting, as well!
0:33:30 > 0:33:32I suppose we'd better go and take a closer look.
0:33:32 > 0:33:35I think we ought to now we're down here.
0:33:35 > 0:33:38WATER GUSHES
0:33:39 > 0:33:41That is truly foul.
0:33:41 > 0:33:45- Really hard.- That's old fat, that.
0:33:45 > 0:33:48- Oh, right.- We'll go back up the top. - Back up again?- Yeah.
0:33:54 > 0:34:00There we go. That's the product of our fast-food burger-eating,
0:34:00 > 0:34:03chip-eating, kebab-eating lifestyle.
0:34:03 > 0:34:06Solid fat.
0:34:07 > 0:34:10Choking up the sewers underneath London.
0:34:10 > 0:34:13Now I want to wipe my nose but, on the whole,
0:34:13 > 0:34:15I think I won't.
0:34:17 > 0:34:22Across the globe, the consequences of the waste crisis in Mexico City
0:34:22 > 0:34:26are on an epic and al fresco scale compared to London's sewers.
0:34:26 > 0:34:29This is what's known as the Grand Canal.
0:34:29 > 0:34:34No gondolas, no palazzos and no tourists either.
0:34:34 > 0:34:38It's a hundred-mile-long open sewer,
0:34:38 > 0:34:44designed to transport waste water to the central sewage works.
0:34:44 > 0:34:48I fear it is time for me to experience sewer cleaning
0:34:48 > 0:34:51on an altogether different level.
0:34:55 > 0:34:58I'm told that at this moment,
0:34:58 > 0:35:03clever people are working on a form of television that you can actually smell.
0:35:03 > 0:35:09And all I can say is, be very glad they haven't got there yet!
0:35:09 > 0:35:12The reek here is unbelievable.
0:35:15 > 0:35:18These canals were designed 100 years ago
0:35:18 > 0:35:22to handle the run-off from Mexico City's rainy season.
0:35:22 > 0:35:24But their history has been overtaken.
0:35:24 > 0:35:27The modern mania for casually throwing things away
0:35:27 > 0:35:31reaches its inevitable consequence here.
0:35:31 > 0:35:36Clogged and festering, almost everything gets tossed in here.
0:35:42 > 0:35:47And the truth is, we are becalmed on a sea of plastic,
0:35:47 > 0:35:52dead dogs - there's one just there - and much worse.
0:35:52 > 0:35:56I am, quite literally, up a certain creek
0:35:56 > 0:35:59with a paddle, which is doing me no good.
0:35:59 > 0:36:04I won't give you the statistics about how much excrement the average human produces each year,
0:36:04 > 0:36:07you don't want to know, except that it's lots,
0:36:07 > 0:36:11or as the scientists would say, lots and lots.
0:36:11 > 0:36:14And so a city the size of this one, with nearly 20 million people,
0:36:14 > 0:36:20produces the equivalent of an Olympic swimming pool-full of excrement every minute,
0:36:20 > 0:36:23and something has to happen to it.
0:36:24 > 0:36:30But blockages can't be got rid of from the relative safety of a boat, or with a spade,
0:36:30 > 0:36:32as in London's ancient sewers.
0:36:32 > 0:36:38This calls for someone with a diver's license, a cool head and a very strong stomach.
0:36:38 > 0:36:44When it comes to unclogging, Ricardo Vazquez is the go-to guy.
0:36:44 > 0:36:46Is it dangerous, what you're doing now?
0:36:46 > 0:36:49HE SPEAKS SPANISH
0:36:50 > 0:36:57- TRANSLATION:- It's dangerous because of all the pollution in the water. Also because of the glass and nails.
0:36:57 > 0:37:00Is there anything you wish you hadn't found?
0:37:00 > 0:37:03Dead bodies.
0:37:03 > 0:37:05Two or three every year.
0:37:05 > 0:37:09I hope you have a good day today. I hope it's not too bad.
0:37:09 > 0:37:12I should say that Health and Safety
0:37:12 > 0:37:15have insisted that I can't go down there.
0:37:15 > 0:37:20And I think, for the first time in my life, I'm thinking, "Go Health and Safety!"
0:37:22 > 0:37:27Once he's submerged, the only contact Ricardo will have with the outside world
0:37:27 > 0:37:29is via a radio in his suit.
0:37:29 > 0:37:34His suit is the only thing between him and the highly toxic broth.
0:37:38 > 0:37:43That's one of the most bizarre things I've ever seen. I mean...
0:37:43 > 0:37:47It's unimaginable, what he's just lowered himself into.
0:37:47 > 0:37:50With glass, nails, sewage
0:37:50 > 0:37:55and maybe even the odd decomposing animal to contend with, it's a risky operation.
0:37:55 > 0:37:58Ricardo now has to dive to the bottom of the tank
0:37:58 > 0:38:01and clear out the filters.
0:38:01 > 0:38:04Down there, I'm told it's completely pitch black.
0:38:04 > 0:38:06So you can't see anything at all.
0:38:06 > 0:38:11What you know is that horrible things are blocking up the system.
0:38:11 > 0:38:14And if they're allowed to keep blocking it up,
0:38:14 > 0:38:19the entire sewage system starts to malfunction.
0:38:23 > 0:38:29There's a metre of just solid trash at this bottom of this, as well, so there's no ground, if you like.
0:38:32 > 0:38:37After five minutes, a radio message comes from the deep.
0:38:37 > 0:38:38He's found a tree.
0:38:38 > 0:38:42While still submerged, working by touch alone,
0:38:42 > 0:38:46Ricardo sets about dislodging the offending tree.
0:38:46 > 0:38:51I can't think of somebody who is more useful to the people of Mexico City
0:38:51 > 0:38:54than the man who's just gone down there.
0:38:57 > 0:38:59Blockage dealt with,
0:38:59 > 0:39:03Ricardo's winched out for a shower and a strong dose of disinfectant.
0:39:07 > 0:39:10The size of the megacity food-and-waste footprint
0:39:10 > 0:39:13threatens the future of the planet.
0:39:13 > 0:39:19But the metropolis has always been a great engine for innovation and radical change.
0:39:19 > 0:39:24And the solutions aren't all top-down or about civil engineering.
0:39:24 > 0:39:28They can start off deceptively small and simple.
0:39:29 > 0:39:31Cooking oil.
0:39:31 > 0:39:33In every city in the world,
0:39:33 > 0:39:38this stuff is as common as cigarette butts and beer cans. It's everywhere.
0:39:38 > 0:39:42Megacities produce millions of gallons of it all the time
0:39:42 > 0:39:46and it's normally seen as a problem.
0:39:46 > 0:39:50You've seen what happens when you stick it down drains and that is not pretty.
0:39:50 > 0:39:54But imagine if it was, in fact, liquid gold.
0:39:54 > 0:39:58An answer to transport problems.
0:39:58 > 0:40:01It's a pretty weird idea,
0:40:01 > 0:40:05but often, salvation...
0:40:05 > 0:40:07is in the detail.
0:40:07 > 0:40:10This restaurant has signed up to a pioneering scheme
0:40:10 > 0:40:16that takes all their waste oil, which would simply get poured away, adding to London's sewer blockages,
0:40:16 > 0:40:19and transforms it into something useful.
0:40:19 > 0:40:22And it's all thanks to this man.
0:40:22 > 0:40:26Every day, Nigel Jewison and his team do their restaurant round,
0:40:26 > 0:40:30picking up drums of dirty, used oil.
0:40:31 > 0:40:34But the HQ for Operation Cooking Oil is here,
0:40:34 > 0:40:37down in the heart of old London.
0:40:37 > 0:40:40Crammed in among the grimy railway arches,
0:40:40 > 0:40:45this mini refinery is a magnet for London's cabbies.
0:40:45 > 0:40:50Hundreds of them queue here every week to get their fill.
0:40:50 > 0:40:54You can see the lovely quality of that oil. That's, er...
0:40:54 > 0:40:57And this is how we like it. Classy restaurant, classy oil.
0:40:57 > 0:41:03- That's not always the case, though. - There's a few restaurants I won't eat at, even with their good names,
0:41:03 > 0:41:05after seeing their waste oil.
0:41:05 > 0:41:09So this is a very straightforward filtration system.
0:41:09 > 0:41:13Dirty oil becomes less dirty oil,
0:41:13 > 0:41:17sits in these tanks and becomes clean-ish oil,
0:41:17 > 0:41:19and then, eventually, clean oil.
0:41:19 > 0:41:22At which point, it can be made into fuel for the taxis.
0:41:24 > 0:41:29- Hiya, Pete. How's it going? Busy on the streets? - It's OK. It could be better!
0:41:29 > 0:41:32- It always can.- Always better. Hello there.- Hiya.
0:41:32 > 0:41:35Have you been doing it for a while, using the biodiesel?
0:41:35 > 0:41:39- Is it good for you, as a taxi driver?- Fantastic.- Why?
0:41:39 > 0:41:42- It's cheaper, for a start. It's cleaner.- Yeah.
0:41:42 > 0:41:48With the new legislation coming on the older cabs, it could be a way to get us to last a bit longer.
0:41:48 > 0:41:51Do you notice the lack of black smoke and smells?
0:41:51 > 0:41:55Definitely. But because it smells of fish and chips, you're always hungry!
0:41:56 > 0:42:02If you go to classier restaurants, it would smell of garlic and all sorts of stuff. Garlicky cabs.
0:42:02 > 0:42:07One of my dreams when I first started up, when people started talking about smells,
0:42:07 > 0:42:12was that, if I could collect all the Chinese restaurants, on another round, Indian restaurants,
0:42:12 > 0:42:16we could open up a filling station with Chinese-smelling fuel, Indian-smelling fuel.
0:42:16 > 0:42:20So you could choose your nationality of fuel!
0:42:20 > 0:42:22It'd be brilliant, wouldn't it?
0:42:22 > 0:42:28- But it's good news for you guys. - I think it's very good. It's a shame they can't put it in buses.- Yes.
0:42:32 > 0:42:37Coming to the amount of cooking oil in the city centre, around London,
0:42:37 > 0:42:42how widespread could this be in fuelling taxis, fuelling cars?
0:42:42 > 0:42:47If we can collect all the oil in London, we could probably fuel all the taxis,
0:42:47 > 0:42:50- which would be a fantastic thing. - Amazing.- It would be.
0:42:54 > 0:43:00If a great city like London had to rely on the elected politicians and the planners for its solutions,
0:43:00 > 0:43:05I think it would be a much less interesting and more constipated sort of place.
0:43:05 > 0:43:09Very often, the big ideas are found
0:43:09 > 0:43:13in the little nooks and side streets of the city.
0:43:13 > 0:43:17And the job of the politicians is to get hold of those ideas
0:43:17 > 0:43:19and, using their taxes and their rules,
0:43:19 > 0:43:25to ensure that they then spread and seed much more widely.
0:43:28 > 0:43:31Putting old cooking oil to good use is one thing,
0:43:31 > 0:43:35but what about all the other stuff we chuck away without a thought?
0:43:35 > 0:43:39Well, that ends up here, in a landfill site.
0:43:39 > 0:43:43London is near to the bottom of the European cities landfill league,
0:43:43 > 0:43:47only recycling about 25 percent of its waste.
0:43:49 > 0:43:54And it's running out of space to dump its growing, growling
0:43:54 > 0:43:56mountains of rubbish.
0:43:56 > 0:44:01The truth is that we in the West throw away far too much.
0:44:01 > 0:44:05I do. You probably do, as well.
0:44:05 > 0:44:08And when we think about it, we may feel a bit guilty.
0:44:08 > 0:44:13And increasingly, we're being kind of mildly bullied
0:44:13 > 0:44:17by councils and government to throw away less.
0:44:17 > 0:44:21But when you come to a place like this,
0:44:21 > 0:44:24you realise why.
0:44:24 > 0:44:27Perhaps we do have to learn from those parts of the world
0:44:27 > 0:44:32where they recycle everything they possibly can.
0:44:40 > 0:44:44In Dhaka, it isn't a case of recycling with a conscience.
0:44:44 > 0:44:48This is the extreme end and it's driven by necessity.
0:44:48 > 0:44:54Here, entire communities are completely reliant on salvaging the scraps,
0:44:54 > 0:44:56the megacity's leftovers,
0:44:56 > 0:44:59to carve out some kind of living.
0:45:01 > 0:45:06It's sort of like when a large animal is killed in the jungle
0:45:06 > 0:45:09and the carcass is picked completely.
0:45:09 > 0:45:12And this is an urban version of the same thing.
0:45:12 > 0:45:16Rather than microbes doing the picking, it's little boys.
0:45:18 > 0:45:23Dhaka's main rubbish dump is the size of a small town,
0:45:23 > 0:45:26and a town with its own people.
0:45:26 > 0:45:30Here, anything that can be melted down or reshaped and reused
0:45:30 > 0:45:33is bagged up and carted off to be resold.
0:45:33 > 0:45:36And when I say anything, I really do mean anything.
0:45:36 > 0:45:38What are you looking for?
0:45:38 > 0:45:40TRANSLATOR SPEAKS BENGALI
0:45:40 > 0:45:46- Plates, cartons, bottles. Plastic... - Plastic. I can understand that.
0:45:46 > 0:45:49And what does she do with them when she's got them?
0:45:49 > 0:45:51SHE SPEAKS BENGALI
0:45:51 > 0:45:54- TRANSLATION: - Takes it to the shops and sell it.
0:45:54 > 0:45:57Everything there is scrunched and dirty.
0:45:57 > 0:46:00These are not bottles that could ordinarily be recycled.
0:46:00 > 0:46:04This is absolutely the leavings of the leavings, the scraps of the scraps,
0:46:04 > 0:46:05the final pickings
0:46:05 > 0:46:08after everybody else further up the food chain
0:46:08 > 0:46:11has taken what's worth something.
0:46:12 > 0:46:16Here, even the insidious plastic shopping bag is given another life,
0:46:16 > 0:46:19melted down and recycled.
0:46:20 > 0:46:23In a sort of most unpleasant way, I suppose,
0:46:23 > 0:46:25poverty is very efficient.
0:46:25 > 0:46:28Everything is used.
0:46:31 > 0:46:33This might seem like a rather hardcore solution
0:46:33 > 0:46:36to the waste problem of the metropolis,
0:46:36 > 0:46:41but perhaps the Dhaka necessity for re-use and recycling
0:46:41 > 0:46:44has lessons for us at home.
0:46:44 > 0:46:49The longer all of us live in the city, the more disconnected we get.
0:46:49 > 0:46:52More of our food is processed and pre-packaged.
0:46:52 > 0:46:56It arrives in cartons and little plastic boxes.
0:46:56 > 0:47:01And instead of being sure about when something has gone off
0:47:01 > 0:47:04and it's no longer acceptable,
0:47:04 > 0:47:07we rely on those rather timid sell-by dates.
0:47:07 > 0:47:09"If in doubt, chuck it out."
0:47:09 > 0:47:14Which is a wasteful way of living and of eating.
0:47:19 > 0:47:22Dinner with Simon and Fran,
0:47:22 > 0:47:25another pair of metropolis innovators.
0:47:25 > 0:47:27They call themselves freegans.
0:47:27 > 0:47:31There's bread here. That's £1.30 for that.
0:47:31 > 0:47:37£1.30 that'd cost in the shop. It's good bakery bread. Nothing wrong with that at all.
0:47:37 > 0:47:38Large whites.
0:47:38 > 0:47:42- Can you find a date on there? - The 16th. That's yesterday.
0:47:42 > 0:47:44Bread doesn't just go off overnight.
0:47:44 > 0:47:47What are these? Diet Pepsi.
0:47:47 > 0:47:51- I'll just pass them to you. - There's a lot of it.
0:47:51 > 0:47:55- You'll be belching for a week!- Yeah!
0:47:55 > 0:47:59It makes me feel gaseous and horrible!
0:47:59 > 0:48:01Just look at this!
0:48:03 > 0:48:07Twice a week for the past two years, Simon and Fran have sifted through the skips
0:48:07 > 0:48:11of the back of London's high-street stores and they've yet to go hungry.
0:48:11 > 0:48:15Apart from the fact that it's good news for you, does it make you angry?
0:48:15 > 0:48:17- It does.- Because of the waste.
0:48:17 > 0:48:23Because there's people in the world who are starving, and we have an abundance and we throw it away.
0:48:23 > 0:48:26What's that? Hold on a minute.
0:48:26 > 0:48:30- What have you got?- Ha-ha! - Chocolates.- Chocolate.- OK.
0:48:30 > 0:48:32Not bad.
0:48:32 > 0:48:35- Why would that be thrown away? - I have no idea. What's the...?
0:48:35 > 0:48:38- February. - Chocolates don't just go off.
0:48:40 > 0:48:45'I don't generally make a habit of routing through rubbish bins, and it does feel a little odd.
0:48:45 > 0:48:49'Legally speaking, however, what's thrown away is fair game.'
0:48:49 > 0:48:53And so to the getaway vehicle! THEY LAUGH
0:48:54 > 0:48:58What's the range of stuff that you're picking up?
0:48:58 > 0:49:01- Meats. A lot of meat that we find. - Yeah.- Cheese. Milk.
0:49:01 > 0:49:03- Yoghurts.- Yoghurts.
0:49:03 > 0:49:08What would you say to people who say, "It's past its best-by date?"
0:49:08 > 0:49:10Use your common sense and have a look at it.
0:49:10 > 0:49:14Best-by date, obviously it's saying, "If you want it perfect, eat it before then."
0:49:14 > 0:49:18But, you know, the food's still perfectly edible.
0:49:18 > 0:49:22Have you ever been unable to feed yourselves
0:49:22 > 0:49:25by freegan... lifting of stuff out of bins?
0:49:25 > 0:49:27- Not in London.- No.
0:49:27 > 0:49:32- There's too much abundance and waste to not be able to do it.- Yeah.
0:49:34 > 0:49:38Simon and Fran's fight against the waste footprint is only half the battle.
0:49:38 > 0:49:43Managing to work out how to supply a metropolis with all the resources it needs
0:49:43 > 0:49:47requires an equally smart way of thinking.
0:49:47 > 0:49:52Food often travels thousands of miles before it arrives on our plates.
0:49:52 > 0:49:55It's inefficient, it's wasteful.
0:49:55 > 0:49:59But to find a solution, perhaps we need to travel back in time.
0:50:06 > 0:50:11Away, at last, from the madness of the megacity.
0:50:11 > 0:50:17Birdsong, nature... Back in the countryside.
0:50:17 > 0:50:20Except that I'm not in the countryside.
0:50:20 > 0:50:24I am inside Mexico City
0:50:24 > 0:50:29and we're on our way to see its famous floating farms.
0:50:29 > 0:50:33They go right the way back as an idea to the original Aztec city,
0:50:33 > 0:50:36which was built on a lake.
0:50:36 > 0:50:40And the way they fed themselves was, the created little floating islands,
0:50:40 > 0:50:46and on those islands, they grew the plants they needed to eat.
0:50:48 > 0:50:53In the 16th century, Mexico City, or Tenochtitlan,
0:50:53 > 0:50:55was the largest city in the world.
0:50:55 > 0:50:59The Aztecs' floating islands, or farms, were vast rafts
0:50:59 > 0:51:04made out of reeds, fertilised with mud from the lake, and organic waste.
0:51:04 > 0:51:09The result was highly productive. An amazing two-thirds of the city's food
0:51:09 > 0:51:12was grown within the city limits.
0:51:13 > 0:51:15DOG BARKS
0:51:16 > 0:51:18Now we're in the 21st century,
0:51:18 > 0:51:22one of the questions is, could we go right the way back?
0:51:22 > 0:51:29Could we learn to grow more of our own food actually inside the city?
0:51:29 > 0:51:33Pedro Castillo is keeping traditions alive
0:51:33 > 0:51:36from before the Spanish Conquest.
0:51:39 > 0:51:41- It's a beautiful.- Claro.
0:51:41 > 0:51:45His fertile little holding of vegetables
0:51:45 > 0:51:49is home to livestock and an abundance of fruit and vegetables,
0:51:49 > 0:51:52which are all sold back to downtown Mexico City
0:51:52 > 0:51:54a couple of miles away.
0:51:54 > 0:51:58Why did they start to grow the food on the island?
0:51:58 > 0:52:01And is it a good way of growing food, to have a floating farm?
0:52:01 > 0:52:03HE SPEAKS SPANISH
0:52:05 > 0:52:08- TRANSLATION: - It was more about necessity.
0:52:08 > 0:52:14It was the lack of space, the lack of room to cultivate their crops that brought them here.
0:52:14 > 0:52:17And then they noticed it was very good for farming.
0:52:17 > 0:52:22So, you yourself, what do you grow here and where do you sell what you grow?
0:52:26 > 0:52:29They grow lettuce, spinach, tomato,
0:52:29 > 0:52:31corn, radish.
0:52:31 > 0:52:33< HE SPEAKS SPANISH
0:52:33 > 0:52:37Normally, they sell it in the market here in Xochimilco,
0:52:37 > 0:52:43- but right now, they're selling to very selective restaurants in Mexico City.- Very good.
0:52:43 > 0:52:49Pedro makes a mean tamale, that's a kind of corn dough served in leaves.
0:52:49 > 0:52:50Mm. Very good.
0:52:50 > 0:52:56And like all good farmers, Pedro does a nice line in home brew, as well.
0:52:56 > 0:53:00This is a traditional tipple which is made out of cactus sap.
0:53:00 > 0:53:06It's got a kind of caramel taste. And it would be extremely rude not to sample it properly.
0:53:06 > 0:53:07It is damn fine!
0:53:07 > 0:53:12Mm! Very good. HE SPEAKS SPANISH
0:53:16 > 0:53:19- TRANSLATION:- You're offering it to the mother earth.
0:53:26 > 0:53:29Of course, this is very much a Mexico City story.
0:53:29 > 0:53:34You don't get tamales and floating farms most places.
0:53:34 > 0:53:36But perhaps there's a lesson here.
0:53:36 > 0:53:39Because although they're built by humans,
0:53:39 > 0:53:42cities depend on nature.
0:53:42 > 0:53:45We're inside nature, we're part of nature.
0:53:45 > 0:53:51And the great cities that we build thrive or die
0:53:51 > 0:53:54because of the natural world around them.
0:53:59 > 0:54:03We tear up the past and we ignore nature at our peril.
0:54:03 > 0:54:08Just like Mexico City, London used to grow a substantial amount of its own food
0:54:08 > 0:54:11within a few short miles of the centre.
0:54:11 > 0:54:15This fertile farmland, known as the breadbasket of London,
0:54:15 > 0:54:19is better known today as Heathrow Airport,
0:54:19 > 0:54:23where food, very often similar food,
0:54:23 > 0:54:28now arrives from South America, Africa, Asia.
0:54:28 > 0:54:32I'm not saying we should rip up and plough what we've built over,
0:54:32 > 0:54:36but we do need to be more clever about how we use what we've got.
0:54:37 > 0:54:43If the future shape of metropolis seems to be ever more dense and increasingly high rise,
0:54:43 > 0:54:48then, maybe, some of the answers to feeding the city have to be urban ones.
0:54:49 > 0:54:54For decades, people have imagined a science-fiction future.
0:54:54 > 0:54:57A vertical city and farms in the sky.
0:54:57 > 0:55:00It's not entirely far-fetched.
0:55:00 > 0:55:04Architects are already hard at work.
0:55:10 > 0:55:14Nearer to hand, inside this inner-city London terrace,
0:55:14 > 0:55:18the seeds of something pretty big could be growing.
0:55:21 > 0:55:26Like most ground-breaking ideas, they start small.
0:55:27 > 0:55:33This is a mini hydroponic and aquaponic farm.
0:55:33 > 0:55:39There is no soil here. The plants are grown under light, in mineral solutions and water,
0:55:39 > 0:55:42fertilised by fish droppings.
0:55:44 > 0:55:48Fresh eggs are laid daily in a rooftop coop.
0:55:48 > 0:55:54I'm under no illusion that a few salad plants and hens are going to solve the food crisis,
0:55:54 > 0:55:58but think how much neglected space London has to offer
0:55:58 > 0:56:03a whole city of potential 21st century urban farmers.
0:56:03 > 0:56:05Farmers like Paul Smith.
0:56:05 > 0:56:09Our big plan is to grow food all around the city,
0:56:09 > 0:56:14in warehouses, empty buildings and old derelict spaces.
0:56:14 > 0:56:17When you're growing inside a building,
0:56:17 > 0:56:21the best way to make use of the space is to grow upwards, create vertical installations,
0:56:21 > 0:56:23layers of food within buildings.
0:56:23 > 0:56:27This a movement happening all around the world that we hope to be part of.
0:56:27 > 0:56:30We're trying to demonstrate you can get the best of both worlds.
0:56:30 > 0:56:33You can have an ecological food system in the city,
0:56:33 > 0:56:37and if you do that, we'll have a much lower food footprint for everybody.
0:56:38 > 0:56:44If we can get enough people growing food in cities, it'll be one part of the picture.
0:56:44 > 0:56:47The city has an absolute, in our view, critical role
0:56:47 > 0:56:51in fulfilling the future food needs of a place like London.
0:56:57 > 0:57:01Over the next century, disasters permitting,
0:57:01 > 0:57:04the growth of the megacities will stretch onwards.
0:57:04 > 0:57:09In the last hour, in the time that it's taken to watch this programme,
0:57:09 > 0:57:137,500 people have moved from the country to a big city.
0:57:13 > 0:57:20In that hour, the world's slum population has gone up by 3,000 people.
0:57:21 > 0:57:24Shanghai's underground, already the longest in the world,
0:57:24 > 0:57:27will have grown by a further five metres.
0:57:29 > 0:57:33And so is the inexorable rise and the dominance of the megacity
0:57:33 > 0:57:37a cause for despair or hope?
0:57:39 > 0:57:42There's no single answer to any of this.
0:57:42 > 0:57:48We need the planners. We need the Shanghai-sized ambitions.
0:57:48 > 0:57:51But we also need the kick from the streets.
0:57:51 > 0:57:54We need the stroppy cyclists, the backyard innovators,
0:57:54 > 0:57:58and the idealistic freegans trying new ways of living.
0:57:58 > 0:58:06Because cities don't belong to the town hall or the architects or the commissars.
0:58:06 > 0:58:09Cities belong to citizens.
0:58:09 > 0:58:13Are they going to be new urban nightmares
0:58:13 > 0:58:18or are they going to be places where we dream new dreams and bring them into effect?
0:58:18 > 0:58:23Well, that's up to me. And you.
0:58:23 > 0:58:27Subtitles by Red Bee Media Ltd
0:58:27 > 0:58:30E-mail subtitling@bbc.co.uk