St. Martins Sea Caves are caves made by the erosion of the ocean. The tide, which rises and falls every 6 hours and 13 minutes can range up to 38 feet.
To explore the caves, go around low tide. You have to cross a little brook to get to the caves. The seaweed makes the rocks slippery, so bring water shoes and be careful.
Fascinating place. I love the outside shot of people about to enter the cave. My first impression was that the rock was a large tree and dwarves were about to enter a hole right above its roots.