This is the most recognizable historical sight of London. The Tower of London had been built by William the Conqueror to protect his subjects and not even once in history has it been conquered by enemies of England. The White Tower with the Norman St. John chapel is the oldest part of the fortress; its walls are 4.6 meters thick. Up until the 17th century the tower had served as a palace, then as Mint, and then a menagerie (until 1834; the only pets left there now are crows).
The Tower of London is mostly famous as a prison. Even the entry gate at the side of the Thames is called "Traitors' Gate", and the tower on the defensive side, where the Princes disappeared, is referred to as "The Bloody Tower". The green yard within the fortress served as execution spot for the most famous prisoners, including those of the royal blood, whose headless bodies rest in the Chapel Royal of St. Peter ad Vincula, a very beautiful structure in such a gruesome place.
Today the Tower of London houses the Royal Armouries (in the White Tower) and the Crown Jewels: the coronation crown, made in 1661 for Charles II, and the Imperial State Crown with the Black Prince's Ruby are guarded by the garrison of Beefeaters (the Yeomen Warders), dressed in traditional costume of the Tudor times.