Guildford Castle is thought to have been built by William the Conqueror, or one of his barons, shortly after the Norman invasion of England in 1066. Used as a Royal Palace, a prison and a private residence, Guildford Castle and grounds was sold to the Guildford Corporation in 1885. The grounds at Guildford Castle opened as public gardens in 1888 to mark Queen Victoria's Golden Jubilee in 1887. The Tower contains a model of the original castle circa 1300, and interpretation panels tracing its history to the present day. There is a visitor platform on the roof offering panoramic views of Guildford. There is a small gift shop on the ground floor of the castle.