Tower of London - Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London, is a historic castle on the north bank of the River Thames in central London, England.
Says Wikipedia, It was founded towards the end of 1066 as part of the Norman Conquest of England. The White Tower, which gives the entire castle its name, was built by William the Conqueror in 1078, and was a resented symbol of oppression, inflicted upon London by the new ruling elite.
The castle was used as a prison since at least 1100, although that was not its primary purpose.
A grand palace early in its history, it served as a royal residence. As a whole, the Tower is a complex of several buildings set within two concentric rings of defensive walls and a moat.
The Tower of London is one of the most popular tourist attractions in the country. Is has been such since at least the Elizabethan period, when it was one of the sights of London that foreign visitors wrote about. Its most popular attractions were the Royal Menagerie and displays of armour. The Crown Jewels also garner much interest, and have been on public display since 1669.