Bridge four-lane highway on the upper level and a pair of railway tracks at the lower level. Tower Bridge in London is different example of a double-decked bridge, with the central section consisting of a low level bascule span and a high level footbridge. A viaduct is made up of multiple bridges connected into one longer structure. The longest and some of the highest bridges are viaducts, such as the Lake Pontchartrain Causeway and Millau Viaduct. A three-way bridge has three separate spans which meet near the center of the bridge. The bridge appears as a "T" or "Y" when viewed
Tower Bridge behind the Olympic rings. The sound travelled backwards and forwards along the walkway, echoing the structure of the bridge. Following the Olympics, the rings were removed from Tower Bridge and replaced by the emblem of the Paralympic Games for the 2012 Summer Paralympics. Tower Bridge was closed to all road traffic for almost three months in late 2016 (1 October to 30 December). This was to allow structural maintenance work to take place. The work included: During this time the bridge was still open to water borne traffic as required by Act of Parliament. The bridge was open to pedestrians