Tower Bridge was completed in 1894 and is instantly hailed as a London icon and one of the great engineering marvels of its age. The Tower Bridge offer fantastic views of many of London’s most famous sights, including St Paul’s Cathedral, sky-scraping Canary Wharf, maritime Greenwich and The London Eye. Special viewing windows make photography easy.

When it was built, Tower Bridge was the largest and most sophisticated bascule bridge ever built (“bascule” comes from the French for “see-saw”). It was a hydraulically operated bridge, using steam to power the enormous pumping engines. The energy created was then stored in six massive accumulators so that, as soon as power was required to lift the Bridge, it was readily available. The accumulators fed the driving engines, which drove the bascules up and down. Despite the complexity of the system, the bascules only took about a minute to raise to their maximum 86 degrees.

http://www.towerbridge.org.uk/TowerBridge/English/BridgeHistory/