Tower Bridge is a combined bascule and suspension bridge in London which crosses the River Thames. It is close to the Tower of London, from which it takes its name, and has become an iconic symbol of London.
The bridge consists of two towers tied together at the upper level by means of two horizontal walkways, designed to withstand the horizontal forces exerted by the suspended sections of the bridge on the landward sides of the towers. The vertical component of the forces in the suspended sections and the vertical reactions of the two walkways are carried by the two robust towers. The bascule pivots and operating machinery are housed in the base of each tower. The bridge’s present colour scheme dates from 1977, when it was painted red, white and blue for Queen Elizabeth II’s silver jubilee. Originally it was painted a mid greenish-blue colour.
Read more at www.towerbridge.org.uk