The Tower of London is a historic castle and fortress located on the north bank of the River Thames. Founded in 1066 as part of the Norman Conquest, the Tower of London was built by William the Conqueror and has, at varying times in its long history, been used as a royal residence, a prison, armoury, treasury and menagerie, amongst other uses. Today the Tower is protected as a World Heritage Site, and is one of the UK's most popular tourist destinations. Visitors may meet the Tower's 'guardian' ravens, embark on a guided tour led by a Yeoman Warder (also known as Beefeaters) and behold the world-famous collection of Crown Jewels.