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.  This building used to serve as a royal residence, the Treasure for the Royal Jewels,  a defence building and a prison.  There has been more blood spilled in this building per square inch than anywhere else in the city.   The Tower of London is sitting right next to the Tower Bridge and across the river from the ultra modern City Hall.