Dover Castle with tourists entering.

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Dover Castle

Top choice in Dover

Occupying top spot, literally and figuratively, in Dover’s townscape, this most impressive of castles was built to bolster the country’s weakest point at the shortest sea crossing to mainland Europe. The highlights here are the unmissable secret wartime tunnels and the Great Tower, but the huge area it sprawls across has a lot of other interesting sights, so allow at least three hours for your visit, more if you stand to admire the views across the Channel to France.

The site has been in use for as many as 2000 years. On the vast grounds are the remains of a Roman lighthouse, which dates from AD 50 and may be the oldest standing building in Britain. Beside it lies the restored Saxon Church of St Mary in Castro.

The robust 12th-century Great Tower, with walls up to 7m thick, is a medieval warren filled with interactive exhibits and light-and-sound shows that take visitors back to the times of Henry II.

However, the biggest draw of all is the network of secret wartime tunnels. The claustrophobic chalk-hewn passageways were first excavated during the Napoleonic Wars and then expanded to house a command post and hospital in WWII. The highly enjoyable 50-minute guided tour (every 20 minutes, included in the ticket price) tells the story of one of Britain's most famous wartime operations, code-named Dynamo, which was directed from here in 1940 and saw hundreds of thousands of soldiers evacuated from the beaches at Dunkirk. The story is told in a very effective way, with video projected sharply onto the tunnel walls and sounds rumbling through the rock. At one point, the entire passageway is consumed in flames and at others visitors are plunged into complete darkness.