Martello tower

By 1936, the village of Slaughden in Suffolk was lost to the North Sea. The villagers used to open their front and back doors to let the sea through. Can you imagine people doing that nowadays?

All that remains is this Martello tower, built to repel Napoleon's forces, but never completed. Nevertheless, it is special: it was the only one built in a cloverleaf shape, it is the most northerly and it is the largest.

It belongs to the Landmark Trust now, and you can stay in it, accessing the front door by that precarious-looking bridge.