Spanning the best part of a mile of San Francisco Bay, the orange-hued Golden Gate has been named by the American Society of Civil Engineers one of the seven wonders of the modern world. An estimated nine million people visit the bridge each year, not including the thousands who run out and back across it in the annual US Half Marathon. Magnificent views of the bridge are afforded from Golden Gate Park.

Sydney Harbour Affectionately known as 'the coat-hanger', Sydney Harbour Bridge opened in 1932 with a central arch soaring 134 metres above sea level, giving a 49-metre clearance for ships. It is the world's widest steel-arch bridge. Nowadays the savvy tourist doesn't just cross the bridge so much as climb it.

The 'harbour climb' has become a rite of passage for everyone from backpackers to incentive-training businessmen. Issued with gloves, a helmet, fleece and safety harness, participants tightrope walk along 1,500 metres of precipitous catwalks, ladders and arches, all the way from one side of the bay to the other.

Bridge on the River Kwai Yes, the Thai bridge actually exists. And not just on celluloid. The nearby town of Kanchanaburi has become a centre for warremembrance tourism, thanks to the bridge and the nearby cemetery, resting place for 7,000 Allied prisoners of war (many of whom died while building the structure). The bridge looks nothing like the bamboo and wood structure featured in the 1957 movie starring William Holden and Alec Guinness. Just like in the film, the original was blown up . . . not by Holden but by aerial bombing. It was rebuilt in concrete and steel. Rather more attractive are the floating guesthouses and restaurants that have sprung up to cater to the tourists.

Bridge of Sighs Venice has the most bridges in the world. (Pittsburgh, rather surprisingly, comes second). The Bridge of Sighs is the most renowned.

The 'Ponte dei Sospiri' was built in 1600, by Antonio Contino, as a link from the inquisitor's room in the Doge's Palace across the Rio di Palazzo to the city's main prison. The bridge took its name from the sounds made by condemned prisoners as they took their last glimpse of the lagoon, the nearby island of San Giorgio, and freedom.

Brooklyn Bridge Of all Manhattan's bridges this is perhaps the most celebrated. However, it's a wonder that it spans Manhattan's East River at all. The early history of the bridge was fraught with disaster . . . it opened in 1883, 81 years after its inception.

Its first engineer, John A Roebling, was killed in a construction accident. His son, Washington Roebling, took over, only to become an invalid after another accident, then directing construction from his bed.

A total of 27 men died on site. A century later the bridge is considered a thing of beauty by both commuters and tourists.

Hiring bikes to cycle the span has become popular, a practice set to boom with the creation of the Brooklyn Bridge Park, which should do for Brooklyn's shore what the Hudson River Park (Battery Park's new esplanade) did for Manhattan's Lower West Side. The less active can appreciate these elegant arches during the Brooklyn Bridge Park Summer Film Series, a six-week free festival showing films about Brooklyn or featuring Brooklyn actors and directors. It takes place on a screen under the bridge.