Bristol Castle

Bristol Castle was a Norman castle built for the defence of Bristol. Remains can be seen today in Castle Park near the Broadmead Shopping Centre, including the sally port. Built during the reign of William the Conqueror, and later owned by Robert FitzHamon, it became an important royal castle and was the scene of several imprisonments and executions. The castle was modified and further fortified between the 12th and 13th centuries under Robert of Gloucester and King Henry III. By the 16th century it was mostly neglected; it was torn down in 1656 under orders from Oliver Cromwell.

Source: Wikipedia