White Tower, London
The keep at the Tower of London is about 90 feet high and the thickness of the walls varies from 15 feet in the basement to around 10 feet at the top. A central cross wall runs the complete height of keep providing extra strength and a means of supporting the wooden flooring. Originally the keep was painted with whitewash leading to its name. The keep has three square corner towers and one circular corner tower to the north east in which the main spiral staircase is situated. The south east of the building is rounded providing the circular shape usually found at the east and of a church and in which is located the castle's chapel.
The basement of the keep is divided into three rooms. The floor is under ground level to the north but is above ground level to the south because the ground that the keep sits on slopes towards the river Thames. The basement was originally only reached by a spiral staircase in the north east round tower. The basement of the keep held the instruments of torture which were used to extract information from prisoners.in the area to the south east is a dungeon known as the 'Little Ease'.