St Michael's Mount, Marazion. During low tide you can walk to St Michael's Mount across a causeway, during high tide the only way to get to the island is via boat. Open to the public but you can not take dogs. The causeway linking the island to the mainland is 500 feet long and was built by the Arch Priest William Moore around 1420's. The island was bought in 1659 by Colonel John St. Aubyn. The descendants have lived in the castle ever since.

Open to the public part of the year for more information go to there offical website at www.stmichaelsmount.co.uk