For over 100 years the Clifton Suspension Bridge, spanning the beautiful Avon Gorge, has been as much the symbol of Bristol as the Eiffel Tower of Paris or the Opera House of Sydney. Since its opening in 1864 meticulous maintenance has ensured that the bridge has never closed. It is easy to forget that this structure which was designed in the 1830s, built in the 1860s and intended entirely for horse-drawn traffic, now carries a staggering total of 4 million cars a year.