Location: North Bank of River Thames, adjacent to City of London Date completed: 1894 Designers/builders: Sir Horace Jones Function: River crossing

Tower Bridge, which crosses the Thames near the Tower of London, is probably one of the world's most distinctive and best known bridges. It is as much a symbol of London as Big Ben or Buckingham Palace. Despite its elaborate gothic revival appearance, it dates only from 1894 and is essentially a very efficient, high-tech (for its time) steel and concrete structure. Prior to its construction, the last down-river crossing was London Bridge, some way up stream. As London expanded and industrialised eastwards, the need for another downstream crossing became acute. The problem was that a conventional bridge would block access by tall ships to the Pool of London, downstream of London Bridge. In 1877 the government formed "A Special Bridge or Subway Committee" to solve the problem, but it was not until 1884 that a design was chosen. This was submitted by Sir Horace Jones (one of the judges). The design centred on two great towers, built on piers sunk into the river, anchored and braced at the top by walkways. The road crossing was split into two bascules (tilting sections) which could be raised by hydraulic steam engines to allow tall-masted ships to pass through. The two side spans were suspension bridges. Overall, the Bridge is 800 ft (244 m) long with a central span of 200 ft (61 m). The two bascules can be raised to a maximum angle of 86 degrees - the precise degree depends on the height of the ship passing beneath, although the bascules are always raised to the full height for a craft with the reigning monarch on board, regardless of size.

Starting in 1886 it took eight years to complete Tower Bridge. First more than 70,000 tons of concrete needed to be sunk into the river bed to provide piers for the towers to stand on. The framework of the towers was made up of 11,000 tons of steel, which was clad in Cornish Granite and Portland stone. The tower was originally to have been clad in brick, but this was changed to its present ornate Gothic style, to harmonise with the nearby Tower of London.