The Tower of London is a historic castle located in central London on the River Thames. It was built in 1078 on the orders of William the Conqueror to serve as a royal residence and fortress. Over the centuries, the Tower of London has also functioned as a prison, place of execution, arsenal, royal mint, zoo, and jewel house. Many famous figures were imprisoned and executed at the Tower, including Anne Boleyn and Sir Walter Raleigh. Today it is a popular tourist attraction guarded by Beefeaters and houses the Crown Jewels.