Dover Castle

Dover Castle overlooks the English Channel at Dover, Kent, on a site founded in the eleventh century and long known as the Key to England for its command of the shortest sea crossing to the European mainland. Its best known structure, the Great Tower, was built in the twelfth century under King Henry II, who spent more than six thousand five hundred pounds on the castle between 1179 and 1188, an enormous sum against an annual royal revenue of around ten thousand pounds. The site also holds one of only three surviving Roman lighthouses in the world, an early second-century octagonal tower of tufa, Kentish ragstone and red brick considered the tallest and most complete standing Roman structure in England. Tunnels cut into the cliffs beneath the castle, first excavated during the Napoleonic Wars, sheltered the underground headquarters from which Admiral Bertram Ramsay directed Operation Dynamo, the 1940 evacuation of Allied troops from Dunkirk.