0:00:19 > 0:00:22On April 14th 1912,
0:00:22 > 0:00:26two giants were on a collision course in the North Atlantic.
0:00:27 > 0:00:33One was a natural leviathan, 15,000 years in the making.
0:00:34 > 0:00:38The other, a massive luxury liner, whose very name, Titanic,
0:00:38 > 0:00:41symbolised the colossal confidence of the age.
0:00:44 > 0:00:47But even though ice conquered steel,
0:00:47 > 0:00:51the iceberg became a mere bit part in the Titanic legend.
0:00:51 > 0:00:57The chances of colliding with a berg this far into the transatlantic shipping lanes were tiny.
0:00:57 > 0:01:02So where did it come from and how did it get there?
0:01:05 > 0:01:08Scientists have worked out how icebergs are conceived
0:01:08 > 0:01:12and how, like an animal presence, they live out their lives on the ocean.
0:01:15 > 0:01:18Now for the first time, we retrace its 4000 mile journey,
0:01:20 > 0:01:24reveal the monumental forces that shaped it,
0:01:24 > 0:01:30and recreate the last moments of one of the most deadly natural destroyers on the high seas.
0:02:03 > 0:02:08This is the untold story of the most famous iceberg in history.
0:02:20 > 0:02:24The rusting hulk of the Titanic continues to haunt us.
0:02:24 > 0:02:28It's a catastrophe which has been minutely documented and scrutinised.
0:02:28 > 0:02:31But the only record we have of the iceberg that sank her
0:02:31 > 0:02:35is a single photograph taken the cold morning after.
0:02:37 > 0:02:39Eye witness reports vary.
0:02:39 > 0:02:42Some say it was 30 metres high and 100 metres wide.
0:02:44 > 0:02:48What we know for certain is that it was a long way from home.
0:02:50 > 0:02:54The collision site was about the same latitude as New York,
0:02:54 > 0:03:00so how did that huge lump of ice travel so far south?
0:03:03 > 0:03:07The International Ice Patrol went into action the year after the disaster.
0:03:07 > 0:03:14Every iceberg season since, March to July, they've tracked bergs over the North Atlantic.
0:03:14 > 0:03:18They've done more than just protect ships.
0:03:18 > 0:03:22They've uncovered the secret life of the most infamous berg of all.
0:03:25 > 0:03:29Each iceberg is unique, a freshwater ice sculpture
0:03:29 > 0:03:33moulded by its individual journey around the polar seas.
0:03:36 > 0:03:40They float low in the water because of the sheer tonnage of ice.
0:03:40 > 0:03:44That's why the tip of an iceberg is no measure of what lies beneath,
0:03:47 > 0:03:51and why to this day they're such a danger to ships.
0:04:04 > 0:04:08But they are notoriously difficult to keep tabs on.
0:04:08 > 0:04:12Day by day they split, fracture and melt, changing their appearance completely.
0:04:15 > 0:04:19Icebergs are masters of disguise.
0:04:20 > 0:04:25The Titanic iceberg had its own secret history.
0:04:25 > 0:04:28But the Ice Patrol has now traced where it came from.
0:04:32 > 0:04:35'Yeah, looks like a berg at about eight miles.'
0:04:35 > 0:04:40Thousands of miles due north of the collision site is Greenland.
0:04:40 > 0:04:4485% of all icebergs found in the North Atlantic
0:04:44 > 0:04:49come from massive ice fjords on Greenland's west coast,
0:04:49 > 0:04:52like this one, at Ilulissat.
0:04:55 > 0:05:01So much ice is travelling down this inlet that it completely covers the water surface...
0:05:04 > 0:05:08..and it leads us to the biggest iceberg production line of them all.
0:05:11 > 0:05:14Julian Dowdeswell, of the Scott Polar Research Institute
0:05:14 > 0:05:19believes this 80 metre wall of mother ice is the most likely birthplace of the Titanic iceberg.
0:05:22 > 0:05:27We're below the height of the ice cliffs on this six kilometre wide front of the ice stream.
0:05:27 > 0:05:31It's incredibly spectacular to be able to look up at the ice itself
0:05:31 > 0:05:35and the colours of blue and white that are mixed together.
0:05:35 > 0:05:40At some places, it's completely evident that very recent calving has taken place,
0:05:40 > 0:05:43that new icebergs have effectively just been born.
0:05:46 > 0:05:49This single wall of ice produces more icebergs
0:05:49 > 0:05:51than anywhere else in the northern hemisphere -
0:05:51 > 0:05:57thousands each year, fed from an ice basin the size of England.
0:05:57 > 0:06:02Icebergs from here take about three years to reach the North Atlantic.
0:06:02 > 0:06:07The iceberg that sank the Titanic would have calved in 1909,
0:06:07 > 0:06:10just as work began on the ship itself.
0:06:40 > 0:06:44But in fact, this was not the beginning of the iceberg's story.
0:06:44 > 0:06:49The ice cliff was its birthplace, but it had been conceived 15,000 years earlier,
0:06:49 > 0:06:52back in the Stone Age, before man had ever taken to the sea.
0:07:00 > 0:07:04Julian has traced back to where it all began -
0:07:04 > 0:07:08400 miles inland from the Ilulissat ice cliff.
0:07:14 > 0:07:18I'm standing close to the centre of the Greenland ice sheet.
0:07:18 > 0:07:23Beneath me is about 3000 metres of ice
0:07:23 > 0:07:28and looking into the distance, I can see nothing but white.
0:07:28 > 0:07:31The iceberg that ended up sinking the Titanic
0:07:31 > 0:07:34would have begun its life here as a snowflake.
0:07:35 > 0:07:41How could a harmless snowflake become capable of ripping open a steel hull?
0:07:41 > 0:07:46The snow that falls here is at first fluffy and not particularly dense.
0:07:48 > 0:07:54As it compacts with depth it becomes a third of its former size.
0:07:57 > 0:08:03Tens of metres below the surface, it becomes so dense it turns to solid glacial ice.
0:08:03 > 0:08:05Bubbles become trapped within it.
0:08:07 > 0:08:11Each bubble holds captive a breath of its conception air.
0:08:11 > 0:08:17A record of the polar atmosphere that it will carry for 15,000 years,
0:08:17 > 0:08:21to be released by an iceberg in the North Atlantic.
0:08:28 > 0:08:31But how does this rock solid ice transform into bergs?
0:08:34 > 0:08:38The agent of change is melt water.
0:08:38 > 0:08:39Through countless artic summers,
0:08:39 > 0:08:44melt water pools on the surface of the ice sheet, before boring down into its heart.
0:08:54 > 0:08:59In this frozen underworld, glaciologists have discovered a labyrinth of passageways
0:08:59 > 0:09:02cutting right through the ice sheet.
0:09:06 > 0:09:11They are fault lines, which orchestrate how an iceberg will form.
0:09:11 > 0:09:15The walls of future icebergs in frozen suspension.
0:09:22 > 0:09:25Centuries before the Titanic was even conceived on the drawing board,
0:09:25 > 0:09:28the blueprint of its nemesis had been laid down.
0:09:31 > 0:09:35But the developing iceberg was still frozen to the Greenland bedrock,
0:09:35 > 0:09:40barely moving for nearly 15,000 years.
0:09:40 > 0:09:44So how did this terrifying beast ever get to the sea?
0:09:52 > 0:09:56In some places, the earth's inner heat warms the base of the ice sheet
0:09:56 > 0:09:58and the lowest layers of ice begin to melt.
0:10:01 > 0:10:05This releases the ice mass from the bedrock.
0:10:05 > 0:10:08This is how the Titanic iceberg,
0:10:08 > 0:10:12and all the other bergs around it, were set in motion.
0:10:20 > 0:10:24Ripped apart by the strains of movement, crevasses open up.
0:10:27 > 0:10:31Scars and weaknesses the iceberg would carry for the rest of its life.
0:10:36 > 0:10:40At a remarkable four miles a year, top speed for an ice stream,
0:10:40 > 0:10:44it slid down the vast Ilulissat drainage basin.
0:10:56 > 0:10:59Under its own weight, it ground up the bedrock,
0:10:59 > 0:11:03absorbing the fragments into its great bulk.
0:11:07 > 0:11:11It would have covered this last 200 miles to the coast
0:11:11 > 0:11:12in less than 50 years.
0:11:17 > 0:11:22Eventually, the vast Ilulissat ice stream narrows into the fjord.
0:11:22 > 0:11:26So much ice is drawn through this bottleneck, and at such speed,
0:11:26 > 0:11:30that the sea in front of the calving front is always choked.
0:11:35 > 0:11:41In 1909, as the Titanic iceberg was accelerating towards the end of its production line,
0:11:41 > 0:11:43work on the ship was just beginning.
0:11:48 > 0:11:53Two thousand miles away, at the Harland and Wolff shipyards in Belfast,
0:11:53 > 0:11:56the largest keel ever was being laid down.
0:11:56 > 0:12:03In both size and luxury, this liner was intended to be Titanic.
0:12:05 > 0:12:09Plate by plate, rivet by rivet,
0:12:09 > 0:12:1440,000 tonnes of steel were assembled within the largest dry dock in the world.
0:12:16 > 0:12:21The Ilulissat glacier, meanwhile, was creating a rival giant.
0:12:21 > 0:12:25Only the mightiest icebergs make it down to the shipping lanes.
0:12:25 > 0:12:30In 1909, Ilulissat was producing just one or two of these mega bergs each year.
0:13:08 > 0:13:09Sometime in the summer months,
0:13:09 > 0:13:14one such megalith would have started towards its date with destiny.
0:13:15 > 0:13:17Perhaps a mile long,
0:13:17 > 0:13:22it might have displaced a billion tonnes of sea water.
0:13:36 > 0:13:39It would have dwarfed even the Titanic.
0:13:42 > 0:13:46In her dry dock, she was being armour plated with inch thick steel,
0:13:46 > 0:13:48the finest grade of the day.
0:13:49 > 0:13:52But even the strongest steel would be no match
0:13:52 > 0:13:55for the millions of tonnes of icy reality ahead.
0:13:57 > 0:14:00Man's confidence in a new age of technology
0:14:00 > 0:14:02was embodied in this one ship.
0:14:05 > 0:14:11Perhaps, for the first time, we became complacent about the power of the natural world.
0:14:14 > 0:14:19More than anything, the Titanic's owners wanted to out-class their transatlantic rival.
0:14:20 > 0:14:23Harland and Wolff worked at double-time.
0:14:25 > 0:14:29While the Titanic project went full steam ahead,
0:14:29 > 0:14:32the mega berg was going nowhere.
0:14:36 > 0:14:41Up near the calving ice front, the icebergs are on the very first part of their journey.
0:14:41 > 0:14:43It's a slow journey to begin with,
0:14:43 > 0:14:50because they're jammed together in this great amalgam of icebergs and brash ice.
0:14:50 > 0:14:56It would have taken the mega berg over a year to edge its way down the 40 mile fjord.
0:15:31 > 0:15:35While the Titanic ship rose up above the Belfast skyline,
0:15:35 > 0:15:37the massive berg was under assault,
0:15:38 > 0:15:43battered and eroded by the relentless jostling of other bergs.
0:15:52 > 0:15:54Within this first year of life,
0:15:54 > 0:15:57the mega berg would have halved its birth weight.
0:15:57 > 0:16:02But it was still a giant, capable of turning lesser bergs upside down.
0:16:09 > 0:16:13That's when they reveal the grit they've scoured from the Greenland bedrock.
0:16:18 > 0:16:20But where the Ilulissat fjord meets the sea,
0:16:20 > 0:16:23the mega berg would have been stopped in its tracks.
0:16:34 > 0:16:38Although the fjord is very deep, its mouth is very shallow.
0:16:38 > 0:16:44The huge keels of mega bergs can easily run aground here.
0:16:44 > 0:16:47The Titanic iceberg was stuck,
0:16:47 > 0:16:50but with other bergs backing up behind it, something had to give.
0:16:56 > 0:16:59It was an unstable situation which, even today,
0:16:59 > 0:17:01can unleash a phenomenal amount of power.
0:17:02 > 0:17:06Living just a few hundred metres from these brooding giants
0:17:06 > 0:17:10is the Inuit fishing community of Ilulissat.
0:17:10 > 0:17:16Here, a home video captured the moment when a modern day mega berg reached its tipping point.
0:17:26 > 0:17:30Two fishermen, Eli and Soren, had a lucky escape.
0:17:32 > 0:17:35'We sailed from Ilulissat a little late that day,
0:17:35 > 0:17:38'other fishermen had already gone.
0:17:38 > 0:17:41'I think it is the reason why we're still alive.
0:17:45 > 0:17:47'We didn't hear anything because we were sailing fast.
0:17:47 > 0:17:52'Normally you can hear signs when an iceberg is going to roll.
0:18:05 > 0:18:08'Eli panicked and screamed and wanted to cut us free.
0:18:18 > 0:18:21'Afterwards we sailed as fast as we could.
0:18:21 > 0:18:24'We could see the big waves, it was dangerous.
0:18:24 > 0:18:26'It was unbelievable.'
0:18:30 > 0:18:33The rolling iceberg produced a terrifying tsunami.
0:18:59 > 0:19:02Eli and Soren escaped it by heading out to sea.
0:19:08 > 0:19:12No records exist from 1910,
0:19:12 > 0:19:17but perhaps the Titanic iceberg had claimed lives even before it had left the Greenland coast.
0:19:22 > 0:19:25By rolling, it had lifted itself over the fjord mouth.
0:19:25 > 0:19:27It was free.
0:19:27 > 0:19:30The mega berg was by now only a half a mile across,
0:19:30 > 0:19:34but it had reached the open ocean.
0:20:26 > 0:20:31Just beyond the fjord is remarkable evidence of the route the mega berg may have taken,
0:20:31 > 0:20:36as it passed through Greenland's coastal waters.
0:20:38 > 0:20:43While at the sea surface, icebergs seem to be drifting serenely out of the fjord,
0:20:43 > 0:20:45at depth, it's quite a different story.
0:20:45 > 0:20:50Where icebergs impact the seafloor with their deep keels,
0:20:50 > 0:20:53ploughing takes place and in fact,
0:20:53 > 0:20:58the whole of the seafloor is a series of cross cut plough marks.
0:21:01 > 0:21:03We have evidence here...
0:21:03 > 0:21:07from side scan sonar records.
0:21:07 > 0:21:12It reveals that almost the whole of the Greenland shelf
0:21:12 > 0:21:19is being cut to ribbons by the actions of many, many iceberg keels.
0:21:19 > 0:21:22Could our iceberg have passed this way?
0:21:22 > 0:21:26The largest iceberg scour marks or plough marks, on the seafloor
0:21:26 > 0:21:30are up to about 20 kilometres in length,
0:21:30 > 0:21:34several hundred metres wide and between five and ten metres deep.
0:21:38 > 0:21:43If the iceberg that sank the Titanic crossed this bit of the Greenland shelf,
0:21:43 > 0:21:48we may even be looking at the plough mark produced by that iceberg.
0:21:55 > 0:21:58Perhaps, sometime in late 1910,
0:21:58 > 0:22:00the massive berg left its calling card
0:22:00 > 0:22:04in the muddy sediments along Greenland's west coast.
0:22:14 > 0:22:19In Belfast, the Titanic's pioneering hull had been completed.
0:22:23 > 0:22:27Now it was her turn to slip into the water for the first time.
0:22:29 > 0:22:33Both giants had broken their ties with the land.
0:22:36 > 0:22:41But while the Titanic was anchored, ready to be fitted out,
0:22:41 > 0:22:43the iceberg took an unexpected turn.
0:22:45 > 0:22:50Ships are buffeted by wind and waves,
0:22:50 > 0:22:53but big icebergs with vast keels
0:22:53 > 0:22:56are pushed around by deep ocean currents.
0:22:56 > 0:23:04In 1911, the Titanic iceberg would have been picked up on the powerful West Greenland current
0:23:04 > 0:23:07and instead of drifting towards the shipping lanes
0:23:07 > 0:23:11and the fatal collision site, it went the other way.
0:23:11 > 0:23:13It headed north.
0:23:15 > 0:23:17In these early stages of its journey,
0:23:17 > 0:23:19it would have seemed no threat to anyone.
0:23:19 > 0:23:21But icebergs are very unpredictable.
0:23:27 > 0:23:32Claude Daley, ice engineer at Memorial University in Newfoundland,
0:23:32 > 0:23:36has studied how young icebergs change personality at sea.
0:23:36 > 0:23:41When my oldest daughter was in high school, she was looking for a science project to work on.
0:23:41 > 0:23:44I suggested that she come and do a test on ice
0:23:44 > 0:23:48and we wondered, well, what could she do on ice?
0:23:48 > 0:23:52And I said, "Why don't we make some small icebergs
0:23:52 > 0:23:54"and see how they melt?"
0:23:57 > 0:24:02We just did tests. The blocks of ice were just floated in water
0:24:02 > 0:24:04and we watched to see what happened.
0:24:07 > 0:24:11The water melts the bottom of the iceberg.
0:24:11 > 0:24:14The waves lap against the iceberg around the waterline
0:24:14 > 0:24:19and a kind of waistline is formed.
0:24:19 > 0:24:21And then the sun melts the top of the ice
0:24:21 > 0:24:25and you get water flowing off the top of the iceberg.
0:24:25 > 0:24:28With these different melting processes,
0:24:28 > 0:24:33what you find is you get pieces of ice that are either hanging over
0:24:33 > 0:24:38if they're above water or there's a tonne of ice sticking out below the waterline.
0:24:38 > 0:24:41There's this tremendous weight pushing down
0:24:41 > 0:24:44and the buoyant forces from the water pushing up
0:24:44 > 0:24:46and that's potential energy.
0:24:46 > 0:24:51They look so peaceful when they're just sitting there.
0:24:51 > 0:24:57It would take an extremely large explosive device
0:24:57 > 0:25:01to come close to the amount of locked in energy in an iceberg.
0:25:05 > 0:25:09Like a coiled spring, an iceberg can unleash this energy at any moment.
0:25:13 > 0:25:18Extraordinarily, these tensions, deep within its frame, have a voice.
0:25:18 > 0:25:22As seawater forces through its crevasses and fissures,
0:25:22 > 0:25:26its creaking body resonates.
0:25:26 > 0:25:30Since each berg is a unique shape and size,
0:25:30 > 0:25:33the Titanic iceberg would have had its own sounds.
0:25:36 > 0:25:40But it might not have reached full voice until the autumn of 1911,
0:25:40 > 0:25:44when the Greenland current dragged it north into the Arctic,
0:25:44 > 0:25:46and a world of sea ice.
0:25:48 > 0:25:51Sea ice can be over a metre thick.
0:25:51 > 0:25:54The very largest bergs plough right through it,
0:25:54 > 0:25:56but the knocks and blows they receive
0:25:56 > 0:26:01cause veins of sea water deep within them to vibrate,
0:26:01 > 0:26:03like the air in a set of organ pipes.
0:26:15 > 0:26:18As they bump their way through the thick sea ice,
0:26:18 > 0:26:21each iceberg resonates to its own music.
0:27:04 > 0:27:08The Titanic iceberg may have been a force for good up here -
0:27:08 > 0:27:11as much a life-giver as a life-taker,
0:27:11 > 0:27:15for when giant icebergs get dragged onwards by the Greenland current,
0:27:15 > 0:27:18they break open natural sea lanes.
0:27:20 > 0:27:24They also stir up nutrients,
0:27:24 > 0:27:29which allow sea mammals such as beluga and narwhal to feed in their wake.
0:27:32 > 0:27:35WHALES CHATTER
0:27:37 > 0:27:42Perhaps the whales are also responding to the extraordinary symphony playing around them.
0:28:02 > 0:28:07Icebergs are part of the delicate ecology in these frozen seas.
0:28:21 > 0:28:24Leaving lesser bergs to freeze in the pack ice,
0:28:24 > 0:28:28the icy megalith drifted on into its middle age
0:28:28 > 0:28:32and the long, dark Arctic winter of 1911.
0:28:41 > 0:28:44Back in Belfast, through those same winter months,
0:28:44 > 0:28:47finishing touches were added to the Titanic's interior.
0:28:47 > 0:28:51No expense was spared to create this floating palace.
0:28:51 > 0:28:56The castle of ice was now 3,000 miles from the shipping lanes,
0:28:56 > 0:29:01and an encounter with the world's largest liner couldn't have seemed more improbable.
0:29:01 > 0:29:04But in the new year, everything changed.
0:29:07 > 0:29:10At the polar ice cap, the West Greenland current curls,
0:29:10 > 0:29:12and turns south.
0:29:12 > 0:29:15It dragged the Titanic iceberg with it,
0:29:15 > 0:29:19down the north-eastern coast of Canada.
0:29:19 > 0:29:23Tickets for the Titanic's maiden voyage were going on sale,
0:29:23 > 0:29:27just as a deadly armada was unleashed from the natural world.
0:29:38 > 0:29:42The weathered surfaces of each berg have their own tale to tell.
0:29:50 > 0:29:56The chips and fractures read like a history of their individual journeys around the polar seas.
0:29:56 > 0:29:59They've been sculpted into icy skyscrapers.
0:30:03 > 0:30:08Even now, the Titanic iceberg would have been huge.
0:30:08 > 0:30:12The above-water ice alone would have rivalled the Colosseum in size.
0:30:18 > 0:30:23Early in 1912, as many as 10,000 battle-scarred giants
0:30:23 > 0:30:26may have emerged from their polar expedition.
0:30:26 > 0:30:30The chances of the ship meeting the berg had just risen dramatically.
0:30:48 > 0:30:54Every day, the Titanic iceberg would have been moving 12 miles further south.
0:30:55 > 0:31:00There were just eight weeks to go before its meeting with the world's most famous ship.
0:31:03 > 0:31:07On the other side of the ocean, the Titanic was almost complete.
0:31:08 > 0:31:12After a day of sea trials, on April 2nd,
0:31:12 > 0:31:17it headed down to Southampton to prepare for its maiden voyage.
0:31:17 > 0:31:21The iceberg's route south was far from plain sailing.
0:31:25 > 0:31:31A ragged, rocky shelf fingering out from the Newfoundland coast snares many passing icebergs.
0:31:45 > 0:31:49Stranded, nearly 2,000 miles from home,
0:31:49 > 0:31:53many Greenland icebergs end up melting along this coastline.
0:32:04 > 0:32:08The Titanic iceberg could easily have met a similar fate,
0:32:08 > 0:32:11but the deep Labrador current pulled it wide of the coast,
0:32:11 > 0:32:14and continued to control its journey south.
0:32:15 > 0:32:20By now, it was a weathered old beast, and the warming temperatures were taking their toll.
0:32:20 > 0:32:24The ancient snowflakes at its centre were still at minus 20 degrees centigrade,
0:32:24 > 0:32:29but its surface was being eaten away by sun and sea,
0:32:29 > 0:32:32and this would change its behaviour radically.
0:32:41 > 0:32:44When you get an old iceberg, they're the least stable.
0:32:46 > 0:32:49If you just tap them with your finger,
0:32:49 > 0:32:51maybe nothing will happen.
0:32:51 > 0:32:53Maybe everything will happen.
0:32:55 > 0:32:57The experiment with my daughter...
0:32:57 > 0:33:01what we found was with a cube of ice floating in water,
0:33:01 > 0:33:03it starts off quite stable.
0:33:09 > 0:33:12But then, as the bottom melts off the ice block,
0:33:12 > 0:33:16it doesn't take long before the ice is unstable,
0:33:16 > 0:33:18and it rolls on its side.
0:33:26 > 0:33:30What's now under the water is a different shape, and it melts off,
0:33:30 > 0:33:33and then again, it rolls.
0:33:33 > 0:33:37And there's a sequence of melting and rolling and melting and rolling,
0:33:37 > 0:33:41and it got faster and faster and faster.
0:33:43 > 0:33:48By the time the piece of ice was down to about the size of a baseball,
0:33:48 > 0:33:52it was rolling constantly. It was alive.
0:33:56 > 0:34:00The iceberg's life was unravelling too.
0:34:00 > 0:34:02Now less than a tenth of its original size,
0:34:02 > 0:34:06it was probably rolling over every three or four days,
0:34:06 > 0:34:08and melting fast.
0:34:08 > 0:34:12It had, at most, two weeks of life left
0:34:12 > 0:34:15as it moved towards the Grand Banks.
0:34:15 > 0:34:18The Banks are a shallow area of sea,
0:34:18 > 0:34:21but scything through them is a deep trough.
0:34:21 > 0:34:25The Labrador current funnels the icebergs down this channel,
0:34:25 > 0:34:28giving it the name "Iceberg Alley".
0:34:30 > 0:34:36At its southern end, it drags the icebergs right into the transatlantic shipping lanes.
0:34:38 > 0:34:42Only 1% of all bergs make it this far south.
0:34:42 > 0:34:46And even at this late stage, the collision might never have happened.
0:34:48 > 0:34:522,000 miles to the east, in Southampton, the Titanic's owners,
0:34:52 > 0:34:56White Star Line, were deciding whether to delay the crossing.
0:34:57 > 0:34:59A national coal strike was in progress,
0:34:59 > 0:35:04and there simply wasn't enough coal at the port to get the liner to New York.
0:35:05 > 0:35:09But the company was so keen to get their star ship underway
0:35:09 > 0:35:13that they borrowed coal from the holds of other vessels.
0:35:21 > 0:35:24On schedule, around midday on 10th April, 1912,
0:35:24 > 0:35:30the Titanic and her 2,227 passengers steamed into the English Channel.
0:36:13 > 0:36:17Seven lucky passengers were dropped off in Queenstown in Ireland,
0:36:17 > 0:36:20and the Titanic headed into the Atlantic Ocean.
0:36:26 > 0:36:31Two days into their journey, they received several warnings about the large amount of ice ahead.
0:36:31 > 0:36:35Captain Smith adjusted his heading to the south.
0:36:35 > 0:36:39In any other year, that might have been far enough,
0:36:39 > 0:36:42but 1912 was a bad year for bergs.
0:36:45 > 0:36:50As the diners in the opulent state rooms finished their evening meal on the night of April 14th,
0:36:50 > 0:36:54the stokers brought another of the ship's 29 boilers on-stream.
0:36:54 > 0:36:59They were steaming through the darkness of the North Atlantic at a cracking 21 knots.
0:37:05 > 0:37:11There's a simple reason why the lookout wouldn't have been able to spot anything ahead...
0:37:11 > 0:37:13until too late.
0:37:13 > 0:37:18Tonight is a night like the night the Titanic hit the iceberg.
0:37:18 > 0:37:19There's no moon.
0:37:19 > 0:37:23It's fairly calm. We can see a few lights in the ocean here tonight,
0:37:23 > 0:37:30and it's the reflection from those lights that let us see objects.
0:37:30 > 0:37:33But if we were the only light in the ocean,
0:37:33 > 0:37:36then the light would be going out from us.
0:37:36 > 0:37:39The Titanic itself was a sea of light.
0:37:39 > 0:37:41Like a city, it lights up the neighbourhood -
0:37:41 > 0:37:43you can't see outside of it.
0:37:43 > 0:37:47Of course, their eyes were accustomed to the light onboard.
0:37:52 > 0:37:55It was much more than the "nothing" that was out around them.
0:38:06 > 0:38:10If we were on the iceberg, we would've spotted the Titanic coming.
0:38:14 > 0:38:17But the reverse was not true.
0:38:21 > 0:38:26In a calm sea, there would have been no wave action around the base of the iceberg.
0:38:26 > 0:38:29It would have been completely black.
0:38:33 > 0:38:37Modern vessels have radar - they didn't have radar.
0:38:37 > 0:38:40Modern vessels have searchlights that reach miles ahead.
0:38:45 > 0:38:4890% of an iceberg,
0:38:48 > 0:38:52or 90% of an ice cube in your glass, is below the water level.
0:38:52 > 0:38:55And so if you can see an iceberg,
0:38:55 > 0:38:57you're just seeing 10% of it.
0:39:09 > 0:39:11They would've needed to get so close to it
0:39:11 > 0:39:15that some of the lights of the vessel shone on the white ice
0:39:15 > 0:39:17and reflected back.
0:39:21 > 0:39:24It would've just completely surprised them.
0:39:26 > 0:39:27Iceberg, right ahead!
0:39:27 > 0:39:31- Thank you. - Their first instinct was to turn.
0:39:31 > 0:39:34- Iceberg, right ahead! - Hard a' starboard!
0:39:36 > 0:39:39It was the worst decision they could have made.
0:39:39 > 0:39:45I've been on ships that have hit ice head-on and come to a sudden stop.
0:39:48 > 0:39:51As the bow of the ship is crushing and crumpling,
0:39:51 > 0:39:55that acts as a buffer, as a cushion.
0:39:56 > 0:39:59Had the Titanic hit head-on,
0:39:59 > 0:40:01the ship would've come to a shuddering stop,
0:40:01 > 0:40:03most people would've been knocked over.
0:40:03 > 0:40:07China's all over the place, pots in the kitchen are on the floor,
0:40:07 > 0:40:09boiling water everywhere.
0:40:11 > 0:40:15They would clean up the mess, seal off the forepeak,
0:40:15 > 0:40:18and carry on their way, and they would have got home again.
0:40:20 > 0:40:26Today, we would say it's obvious - train people to hit icebergs head-on.
0:40:26 > 0:40:32But it isn't a natural thing, to run into a wall at high speed.
0:40:32 > 0:40:34It isn't natural.
0:40:34 > 0:40:39It's completely understandable that they tried to avoid a major accident.
0:40:44 > 0:40:47'Ships turn very slowly,
0:40:47 > 0:40:50'and the Titanic turned particularly slowly -
0:40:50 > 0:40:54'it had a relatively small rudder for the size of the vessel.'
0:40:56 > 0:41:02It would have been agonising to wait for this large ship
0:41:02 > 0:41:06to slowly take on a new heading.
0:41:06 > 0:41:09While that was occurring, of course,
0:41:09 > 0:41:11the iceberg was coming closer and closer,
0:41:11 > 0:41:15and it would have all been in a kind of slow motion.
0:41:15 > 0:41:19The order was given to put the engines in reverse.
0:41:21 > 0:41:25I think that was a bad idea, I think that was a really bad idea.
0:41:25 > 0:41:31The rudders work because they have high speed flow over them.
0:41:31 > 0:41:37It seems to me it was done out of a kind of panic, that's all I can think,
0:41:37 > 0:41:41because those two actions don't make sense together.
0:41:57 > 0:42:02'And instead of flooding one part of the vessel which no passenger ever went to,
0:42:02 > 0:42:06'they ripped open big parts of the vessel,
0:42:06 > 0:42:09'flooding the engines, flooding the cargo spaces,
0:42:09 > 0:42:12'flooding parts of the vessel that they needed to stay dry'
0:42:12 > 0:42:17if it was going to stay upright and stay floating in the water.
0:42:23 > 0:42:28This meeting, 15,000 years in the making, lasted seconds.
0:42:28 > 0:42:31A blink of an eye in the iceberg's long lifetime.
0:42:35 > 0:42:40Even a rigid steel hull is but paper to half a million tonnes of solid ice.
0:42:40 > 0:42:44A fatal oversight, which cost over 1,500 lives.
0:42:52 > 0:42:55While news of the tragedy tapped along the wires,
0:42:55 > 0:42:57the iceberg floated on.
0:42:57 > 0:43:01Some see an incriminating scrape of paint on its surface.
0:43:06 > 0:43:08But all we can really tell from its appearance
0:43:08 > 0:43:13is that it would have been rolling continually, highly unstable.
0:43:13 > 0:43:15A berg that was in its own death throes.
0:43:19 > 0:43:23Warmer Gulf Stream water was eating voraciously into its heart.
0:43:31 > 0:43:35The ancient leviathan had been reduced to a shard of ice.
0:43:45 > 0:43:50Titanic had been expected to make many journeys through these waters,
0:43:52 > 0:43:57but the iceberg's maiden voyage was always to be its last.
0:44:17 > 0:44:20In late April 1912,
0:44:20 > 0:44:23barely a week or two after the Titanic's demise,
0:44:23 > 0:44:26over 1,000 miles from its birthplace,
0:44:26 > 0:44:30the last piece of the iceberg disappeared into the Atlantic Ocean.
0:44:32 > 0:44:35Some way from the rusting hull of the Titanic,
0:44:35 > 0:44:37there would be a scattering of soil
0:44:37 > 0:44:40where the last of the iceberg's rocky sediments
0:44:40 > 0:44:42was finally released into the ocean.
0:44:51 > 0:44:54The iceberg was remembered as a destructive force,
0:44:54 > 0:44:57but was the tragedy that befell the liner
0:44:57 > 0:45:00as much to do with our own over-reaching ambition?
0:45:05 > 0:45:08The disaster made us pay attention to icebergs.
0:45:08 > 0:45:12In the decades since, fear of them has turned to wonder.
0:45:15 > 0:45:20We've come to appreciate them as remarkable and beautiful natural objects.
0:45:20 > 0:45:23More recently, we've learned that they,
0:45:23 > 0:45:25and the currents which transport them,
0:45:25 > 0:45:28play a crucial role in regulating our climate.
0:45:32 > 0:45:38There is a delicate balance between the amount of ice melting from the Greenland ice sheet
0:45:38 > 0:45:41and the way in which currents flow through the Atlantic ocean.
0:45:41 > 0:45:45Global warming is threatening this balance.
0:45:47 > 0:45:50Scientists predict that a flood of polar melt water
0:45:50 > 0:45:54could change the salinity of the North Atlantic,
0:45:54 > 0:45:56weaken the Gulf Stream,
0:45:56 > 0:46:00and bring a bit of the Arctic permanently to European shores.
0:46:04 > 0:46:09Preserving the world's polar regions has never been more important.
0:46:49 > 0:46:53Every year, the International Ice Patrol honours the lost souls of the Titanic
0:46:53 > 0:46:55with a wreath drop over the wreck site.
0:46:56 > 0:46:59'It is with great respect and reverence
0:46:59 > 0:47:05'that we commemorate this anniversary of the sinking of the RMS Titanic on April 15th, 1912.
0:47:05 > 0:47:10'We remember the over 1,500 souls who perished on that fateful day.
0:47:10 > 0:47:13'On behalf of the United States Coastguard,
0:47:13 > 0:47:18'and the family and friends of those who perished with the sinking of the Titanic, we cast these wreaths.'
0:48:20 > 0:48:22Subtitles by Red Bee Media Ltd - 2006
0:48:22 > 0:48:24Email subtitling@bbc.co.uk