0:00:02 > 0:00:06BBC Four Collections - archive programmes chosen by experts.
0:00:06 > 0:00:10For this collection, Janet Street-Porter has selected
0:00:10 > 0:00:12programmes about post-war architecture.
0:00:12 > 0:00:15More programmes on this theme and other BBC Four Collections
0:00:15 > 0:00:17are available on BBC iPlayer.
0:00:36 > 0:00:38WIND WHISTLES
0:00:46 > 0:00:49Up here in the gods,
0:00:49 > 0:00:53you really get the feeling that you're part of something fundamental.
0:00:53 > 0:00:56Not just because this is one of the modern wonders of the world,
0:00:56 > 0:01:00but it's one of those monumental locations
0:01:00 > 0:01:02on the surface of the planet.
0:01:07 > 0:01:11It's not just the longest span in the world, it's also the loneliest,
0:01:11 > 0:01:15surrounded by lowland and sea level.
0:01:16 > 0:01:19It seems to exaggerate all of its proportions,
0:01:20 > 0:01:22and makes it a landmark in every sense of the word.
0:01:28 > 0:01:30Or a watermark, even,
0:01:30 > 0:01:33set against those pale horizons of water and sky.
0:01:46 > 0:01:48LOW BUZZING
0:01:52 > 0:01:56Closed-circuit TV, monitors, surveillance,
0:01:56 > 0:01:58smoked glass, uniforms,
0:01:58 > 0:02:01documents being examined, money changing hands.
0:02:01 > 0:02:04There's something a little bit sinister
0:02:04 > 0:02:06about the control tower and the tollbooths,
0:02:06 > 0:02:08something a little bit Big Brother,
0:02:08 > 0:02:09or Eastern European, even -
0:02:09 > 0:02:12reminiscent of a border crossing or a checkpoint.
0:02:12 > 0:02:16The barriers and the signals are the sort you might come up against
0:02:16 > 0:02:19at a frontier between two territories.
0:02:19 > 0:02:22And those vehicles making the journey at dawn or at dusk
0:02:22 > 0:02:25look like they're leaving for a new world across the water.
0:02:35 > 0:02:38The Greenwich meridian actually crosses the Humber,
0:02:38 > 0:02:42and if it were a real thing rather than an imaginary line,
0:02:42 > 0:02:44it would probably look something like this.
0:02:44 > 0:02:46Underneath, it's a road to nowhere,
0:02:46 > 0:02:48giving the impression of being never-ending
0:02:48 > 0:02:51or having no real destination or point of arrival.
0:02:51 > 0:02:53Like a rainbow.
0:02:54 > 0:02:58And on top, it's so much more than a way of getting from A to B.
0:02:58 > 0:03:00It's an art installation of some type,
0:03:00 > 0:03:04celebrating the ideals of balance and symmetry and poise.
0:03:06 > 0:03:09Personally, I find it very satisfying
0:03:09 > 0:03:12that the greatest bridge of its type should be here,
0:03:12 > 0:03:14spanning the mud flats of Humberside,
0:03:14 > 0:03:17or the East Riding of Yorkshire, as I like to think of it.
0:03:19 > 0:03:21It's also a tug of war going on between two shorelines,
0:03:21 > 0:03:24or a harp that plays when the wind blows through it,
0:03:24 > 0:03:27or a cat's cradle strung out across a river.
0:03:31 > 0:03:34Or spun out, I should say.
0:03:34 > 0:03:36It's hard to believe, but the main cables are made up
0:03:36 > 0:03:39of one continuous strand of wire
0:03:39 > 0:03:41just a few millimetres thick.
0:03:41 > 0:03:45And during construction, a spinning wheel carried the thread
0:03:45 > 0:03:47up and over the shoulders of one tower,
0:03:47 > 0:03:53out across the river to the far side, and back again, about 15,000 times.
0:03:53 > 0:03:57Like winding a length of wool onto two outstretched arms.
0:04:08 > 0:04:10The bridge is so long,
0:04:10 > 0:04:14it has to take into account the curvature of the Earth,
0:04:14 > 0:04:18which is worth bearing in mind when it comes to walking across it -
0:04:18 > 0:04:20stepping out into the wild blue yonder.
0:04:22 > 0:04:25The best way of understanding a suspension bridge
0:04:25 > 0:04:27is to think of a washing line,
0:04:27 > 0:04:31where the towers are the props, the cable is the line itself
0:04:31 > 0:04:34and the road is the washing blowing around in the breeze.
0:04:34 > 0:04:37It's also about suspension of disbelief,
0:04:37 > 0:04:39because if you thought about it for too long,
0:04:39 > 0:04:40you'd never set foot on it again.
0:04:40 > 0:04:43It's completely improbable.
0:04:50 > 0:04:54The roadway itself was the last part of the bridge to be built.
0:04:54 > 0:04:57It's made up of steel boxes hoisted into position
0:04:57 > 0:04:58and spliced together.
0:05:12 > 0:05:13The boxes are hollow,
0:05:13 > 0:05:16making the inside of the bridge a corridor,
0:05:16 > 0:05:19through hundreds of metal rooms, or tanks.
0:05:27 > 0:05:31Looking through them is a trick of the light, a time tunnel,
0:05:31 > 0:05:35doors disappearing inside each other, all the way to infinity.
0:05:38 > 0:05:40In summer it's like an oven.
0:05:42 > 0:05:44And like a freezer in winter.
0:05:44 > 0:05:46RUMBLING AND SCREECHING
0:05:48 > 0:05:51And deafening all year-round with the thunder of traffic
0:05:52 > 0:05:53just inches overhead.
0:06:04 > 0:06:06FOOTSTEPS ECHO
0:06:23 > 0:06:26This is one of the four inner sanctums, the southeast anchorage.
0:06:26 > 0:06:29where all of the wire that makes up one of the main cables
0:06:29 > 0:06:34is held in position by good old-fashioned nuts and bolts.
0:06:34 > 0:06:37You have to keep reminding yourself that this isn't
0:06:37 > 0:06:39hundreds and thousands of different wires.
0:06:39 > 0:06:44It's all one - 22,000 miles of it, looped over and lashed together.
0:06:44 > 0:06:47It could be the inside of a grand piano.
0:06:47 > 0:06:51Everything here is very finely tuned, highly strung.
0:06:51 > 0:06:56It's hard not to think of a catapult, or a crossbow drawn back.
0:06:56 > 0:06:58There's a precarious silence
0:06:58 > 0:07:02which seems to match the tension and force and pressure of this place.
0:07:11 > 0:07:14It's almost cathedral-like in here.
0:07:14 > 0:07:16It makes you feel like whispering,
0:07:16 > 0:07:20or lighting a candle, or leaving money in a box.
0:07:49 > 0:07:51Most of the water in the north of England runs through here,
0:07:51 > 0:07:54so I can think of the bridge as something that symbolises
0:07:54 > 0:07:57the coming together of all those rivers and streams
0:07:57 > 0:08:00that stretch back like arteries into the heart of the country.
0:08:00 > 0:08:04And going inland, the Humber comes out of the River Ouse,
0:08:04 > 0:08:06which comes out of the Aire, which comes out of the Calder
0:08:07 > 0:08:10which comes out of the Colne that springs in the village where I live.
0:08:10 > 0:08:13So, technically, I could sail home from here.
0:08:13 > 0:08:16And if I'd been away at sea, this bridge would be the perfect gateway
0:08:16 > 0:08:19to look out for and come back through.