On the south English shores of the Jurrasic Coast, you can find this iconic limestone arch sticking out from the pebble beach. The scenic C-shaped Lulworth Cove is also close by and it's a nice walk along its shores.
Found on the Kent coastline, these artillery castles were originally built by King Henry VIII. Walmer has been converted into the Lord Warden's stately-home and Deal is now a museum with a permanent exhibition.
Being Britain's closest point to Europe, the city has been built to defend against invasions. The fortress dates back to the 11th century and there are WW2 war tunnels with a tour providing a vicarious experience.