1176-1831
To place a slab of breathing, teeming city over water is an idea of both poetic simplicity and plain commercial practicality. It is only surprising that it is not done more often, such that the few examples are world famous, like the Ponte Vecchio in Florence. London Bridge, as it was until the mid-18th century, would have made the latter look puny, being a multistorey structure like an ocean liner built of stone. That it no longer exists gives it the power of a myth and has also rescued it from being the hell of touristic exploitation that it would now undoubtedly be.
Photograph: Stapleton Collection/Corbis
First documented in the 19th century
This idea is simply fantastic, born, as such things often are, out of necessity. In north-east India, in a region that describes itself as the wettest place on Earth, bridges are woven out of the living roots of trees, because that is the best method available. They grow stronger over time, can last hundreds of years and can carry dozens of people. If a bridge usually seems to be a defiance of nature, or at least a contrast, these grow out of it. It is also striking that they look like computer-generated science-fiction structures, only more interesting. Photograph: National Geographic Image Collec/Alamy
2004
It would easy to fill a list of top 10 bridges with classics of breathtaking engineering – the Golden Gate, the Clifton Suspension Bridge – but the category is here represented by a more modern example. The work of the engineer Michel Virlogeux and the architects Foster and Partners, its attributes are its height – more than the Eiffel Tower at its greatest – length and apparent lightness. The pillars and deck of the cable-stayed structure look impossibly slender, like lines pencilled in the sky. At the same time, the viaduct is equal to the large-scale landscape in which it stands. Photograph: Archaeo Images/Alamy
1999
It would also be easy to fill a list of top 10 bridgeswith examples from Switzerland. Here, necessity - the country has a lot of valleys that need crossing - combines with ability, the national genius for building with precision and skill. The Punt da Suransuns, designed by Conzett Bronzini Gartmann, exemplifies this; although made of steel and grantie if hangs effortlessly like a hammock. Often, the designers of bridges like to make a spectacle out of the effort of holding it up, with straining wires and masts. This is the opposite, aiming, rather, to create a moment of manmade grace on a walk through the landscape. Photograph: www.viamala.ch
1930
Switzerland again, and the work of the great engineer Robert Maillart, who pioneered techniques of reinforced concrete construction. His influence can be seen in the bridges you see crossing almost any motorway, and in the extravagant structures of Santiago Calatrava. But, where the former are more prosaic, and the latter overblown, a bridge such as Salginatobel balances purpose and beauty. Maillart, however, was not completely happy with it – “It cannot lay claim to complete sincerity of form,” he said, as a slight point in the arch would have more truly reflected the structural forces at play. Photograph: Prisma Bildagentur AG / Alamy/Alamy
This is not the greatest bridge in the United States, nor in Oregon, nor possibly on the Willamette river, but it owes its fame to Railroad Turnbridge, a 19-minute 16mm film in which the sculptor Richard Serra placed a camera on its rotating mechanism and recorded its implacable movements of uncoupling, turning and coupling. The result is a meditation on machinery in which the landscape, glimpsed through the girders, seems more unstable than the moving mechanism. Through the film, the bridge comes to stand for the very many pieces of engineering, often quietly impressive, that populate the American landscape. Photograph: UC Berkeley Art Museum
Completed 1877
This is a simple diagram of necessity – a railway line had to be brought across the river Douro and it was impossible to build piers on the river bed. So Gustave Eiffel devised an arch wider than any previously built, its structure widening where the forces are greater, with the dead-straight line of the tracks above. Sometimes untested techniques were used to keep it light and to solve the problem of keeping it up during construction, before the arch was complete. Yet this work of pure engineering also succeeds in being an emblem of its city, something Eiffel would achieve later with a tower in Paris. Photograph: S. Forster/Alamy
1991
Nanpu Bridge is mostly a large cable-stayed structure of a type that, while impressive, is common enough. Indeed, it is the 57th longest of its type in the world, which is unspectacular. What makes it interesting are its approach ramps, giant overlapping spirals that look like fantasy versions of future cities going back to the 1930s, only here made real. An early sign of China’s rise in economic power, it expresses its energy and scale. Also, in its unblinking dedication to car traffic, and its obliviousness to whatever bits of city might be nearby, modern China’s ruthlessness. Photograph: Alamy
1805
To take a waterway through the sky is the stuff of dreams but Thomas Telford’s Pontcysyllte Aqueduct intends nothing more than to take a transport route, the Llangollen Canal, from A to B, with cast-iron troughs supported on masonry piers. Like old London Bridge, it is an example of the inadvertent surrealism of pragmatic decisions. To travel over it in a narrowboat is, however, sublime – on the one hand the serenity of waterborne transport and of the surrounding scenery, on the other hand the pure vertigo engendered by the sheer drops on either side of the narrow channel. Photograph: Paul Thompson Images/Alamy
c1650
Bridges can be tools, the means of crossing water, and objects – impressive feats of structure to be admired at a distance. They can also be places, destinations in their own right, where the experience of being there is as important as the function of getting across. Which, in the end, is the most satisfying – once you have gawped at an amazing suspension bridge, and exploited its usefulness, it doesn’t offer much more. The purposes of the Khaju Bridge included public meetings, a teahouse and enjoying the view, while also functioning as a sluice. Like old London Bridge, it takes the city across water and with more handsome, less ramshackle architecture. Photograph: Robert Preston Photography / Ala/Alamy
