St Michael's Mount

A tidal island off the coast of Cornwall crowned by a medieval castle and church, the home of the same family since the 17th century. At low tide, walk across the ancient cobbled causeway from Marazion; at high tide, take a small boat.

Climb up to the castle for views across Mount's Bay, and visit the subtropical terraced gardens on the cliffs (open in summer). Check the tide times and opening days before you go, as the castle isn't open every day. It's managed by the National Trust.