England, London. Tower Bridge was completed in 1894, after eight years of construction. 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.