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
Richmond Bridge, London from its general west to east direction, flowing from southeast to northwest in this part of London, what would otherwise be known as the north and south banks are often referred to as the "Middlesex" (Twickenham) and "Surrey" (Richmond) banks respectively, named after the historic counties to which each side once belonged. The bridge was widened and slightly flattened in 1937–40, but otherwise still conforms to its original design. The eighth Thames bridge to be built in what is now Greater London, it is today the oldest surviving Thames bridge in London. The small town of Sheen on the Surrey