The Tower of London is one of the world’s most famous fortresses and has seen service as royal palace, prison, armoury and even a zoo.t was built on the Thames by William the Conqueror to protect London and assert his power. The Tower is still home to her Majesty's Crown Jewels, on display for visitors to see.The Tower is said to be haunted by the ghost of Anne Boleyn walking the chapel of St Peter and Vincula.