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 except in the case of a vessel with the Monarch on board in which case they are raised fully no matter the size of the vessel. The Tower Bridge Exhibition is a display housed in the bridge's twin towers, the high-level walkways and the Victorian engine rooms. It uses films, photos and interactive displays to explain why and how Tower Bridge was built. Visitors can access the original steam engines that once powered the bridge bascules, housed in a building close to the south end of the bridge. The exhibition charges an admission fee. Entrance is from the west side