All that remains above ground of Winchester Castle is the Great Hall, the rest having been destroyed on the orders of Oliver Cromwell after capturing it from Royalist forces in 1646.
Although the castle was originally constructed in 1067, Henry III (who was born at Winchester Castle) replaced the hall with the current building between 1222-1235.
Dominating one of the end walls is an imitation Arthurian Round Table. This is old, originally constructed in the 13th century, but not old enough to have anything to do with Arthur. It was repainted in its present form for Henry VIII. Around the edge of the table are the names of King Arthur's knights and in the centre is the Tudor Rose.
For opening times and suggested donations, please see the official site, detailed below.