"This railway bridge spanning the estuary of the Forth River in Scotland is the world’s longest multi-span cantilever bridge. It opened in 1890 and continues to carry passengers and freight. Its distinctive industrial aesthetic is the result of a forthright and unadorned display of its structural components. Innovative in style, materials and scale, the Forth Bridge is an important milestone in bridge design and construction during the period when railways came to dominate long-distance land travel. "
Source UNESCO WH website http://whc.unesco.org/en/list/1485