The royal palace and fortress of the Tower of London, founded by William the Conqueror shortly after 1066, is one of the world's most famous and spectacular castles. Known for housing the Crown Jewels, its Yeoman Warders ("Beefeaters") and its ravens, the Tower today is the most visited historic site in Britain.

The White Tower, oldest of all the Tower buildings, was originally built as a royal palace and fortress, but has also served as a prison, a royal chapel, a record office and a large storehouse of arms, armor and gunpowder.