The Tower of London is a historic castle located on the River Thames in central London. It was founded in 1066 after the Norman conquest as a royal fortress and palace. The White Tower, built around 1078, was the first building and symbolized Norman power. Over the centuries, the Tower of London served as a prison, royal mint, menagerie, and observatory in addition to its roles as a palace and fortress. It remains a popular museum housing the Crown Jewels and chronicling its long history.