Tower Bridge was being built from 1886–1894. It is a combined bascule and suspension bridge. Due to it being close to the Tower of London, it takes its name from it. It is 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 machinery can be inspected if you pay for a tour of the bridge.