What exactly is a sea stack? Watch this video from Drone Director to find out. He filmed some very brave climbers tackling a sea stack north of the island of Kunoy in the Faroe Islands, the Danish-controlled archipelago in the North Atlantic. Sea stacks are essentially giant rocks protruding from the floor of the North Atlantic Ocean. This particular sea stack is called Oldan, and it's located just to the north of the island. If it looks small, it's only by comparison to the giant cliffs of the island!