Sea caves are a coastal cavern chamber or system of chambers connected to the sea or coastal area. They may be part of coastal cliffs. They may be small, or large enough for ships to enter (and potentially transit). They may lead to underground towns, shipwreck towns, or other subterranean elements. They may have chambers that flood with the tides or may only be accessible during especially low tides. They may lead to underground seas or be home to leviathans. They are often used during treasure hunts and may be found on treasure islands.