Between Richmond and the North Sea, thirty bridges span the Thames. They carry people across a stretch of river 35 miles long, bringing together a population of nearly eight million. These extraordinary structures have been the making of London, Britain’s capital, and I think, Europe’s greatest city.

Millions of Londoners cross these bridges every week. Most, I don’t suppose, give them a second thought. But for me, bridges are much more than merely a means of transport – ways of getting from one place to another. They are also ways of linking the present to the past. London’s Bridges are not just functional objects – they’re also symbols, metaphors, which transform, connect, inspire, and they tell great stories. Of Bronze-Age relics of the Vauxhall shore, of why London Bridge was falling down, of corpses splashing beneath Waterloo Bridge, and, above all, of the sublime ambition of London’s bridge builders themselves. I was born when London was still one of the world’s great ports and the Thames one of the world’s great working rivers. I well remember, as a child, the impression that London’s bridges made on me. I suppose bridges gave me my first thrilling, stomach-churning architectural experience. And, goodness me, they are doing the same now.

Some of London’s bridges have vanished or been replaced. They are ghost crosses of the past, but each of them is a clue to the city’s hidden history. In some ways they ARE that history: a history that has lasted nearly four thousand years.