In 1931 the George Washington Bridge opened in New York. It connects Fort Lee in New Jersey with Manhattan over the Hudson River. The length of its central span, at 1,067 metres, was remarkable at the time. It marked a 90% increase over the previous world record of 564m for the Ambassador Bridge in Detroit, which opened two years earlier.

The bridge designer and chief engineer was Othmar Ammann. He sited the New York tower on land and employed John A Roebling & Son’s company (of Brooklyn Bridge fame) to erect the wire cable suspension system. The bridge opened with a single deck but Ammann designed it to accommodate a second, truss-stiffened deck that could be added at a later date. This foresight was rewarded when increased traffic required more capacity. The lower level deck was added between 1959 and 1962 and carried out without interruption to the eight lanes above. Indeed it is still regarded as one of the busiest bridges in the world carrying around 300,000 vehicles a day.