|"London Bridge is falling down, falling down, falling down, London Bridge is falling down...my fair lady." The thing is, it's still up, and attracting visitors from all over the world! Contrary to popular belief, London Bridge actually refers to several bridges that span the River Thames between the City of London and Southwark, in central London. The current crossing is a box girder made from steel and concrete. It opened to traffic in 1973 and replaced a 19th century stone-arched bridge. When most people think of London Bridge, perhaps one of the city's most famous and well-known landmarks, what they are most likely referring to is Tower Bridge. Opened in 1894, it is a hydraulic bridge that can be raised to permit traffic to pass underneath. From the bridge, visitors can enjoy stunning views of the River Thames. Additionally, there is a museum that explains how the bascule bridge operates, and gives detailed information about its history. The Tower Bridge museum is an exciting way to see one of the most famous bridges in the world. After watching an educational video which explains why, and more importantly, how, the bridge was built, it is possible to walk to the high level walkways, 42 metres above the River Thames. It provides stunning views of the London city skyline. There is also a chance to see a photography exhibition dedicated to the "Great Bridges of the World." And in the Victorian Engine Rooms, it is possible to see original lifting machinery, complete with sounds and smells.