Long ago this was an actual island, but thanks to the accretion of sand, it is an island no longer. Its high mounded shape at the edge of the water made for good vistas for whaling. The Punonakanits and Wampanoags actively fished here. Later, European settlers built whale lookout towers and a tavern for the whalers. Now, Great Island is deserted. It's part of the Cape Cod National Seashore - a protected area of beaches, salt marshes, and pine forest. There are a few nice walking trails. The public parking area has seasonal bathrooms. A trail will take you to the tavern site, but only a small marker remains.