In a city filled with historic landmarks, the Tower of London is among its most famous. On the right is the White Tower. This 89 foot tall, central keep was ordered by William the Conqueror. Construction of the Norman castle using Caen Stone and Kentish Ragstone began around 1078. The first phase of the donjon was finished at the end of the century. After Henry III ordered it to be whitewashed in 1240, it became known as the White Tower. Over the millenniums, additional buildings were added to the 12-acre royal residence. An example is the Beauchamp Tower on the left. King Edward I ordered architect Master James of St George to build it in the late 13th century. Within its walls were numerous famous prisoners including Anne Boleyn – the second wife of Henry VIII – and Lady Jane Grey. Both queens were beheaded for treason during the first half of the 16th century. In the foreground are the casements. This tall curtainwall forming the outer ward is surrounded by a moat.