Billingsgate Island
Wellfleet's own version of Atlantis lies south of the southernmost tip of Great Island in Wellfleet Harbor. Billingsgate was about a mile long and half a mile wide in the mid-1800s, with a lighthouse, a school, a plant for rendering whale oil, and a community of 30 houses.
Even by then, the island was slowly disappearing; 1,000 feet of jetties and bulkheads were built around Billingsgate in 1888 to try to slow erosion, but the tide and storms kept taking pieces of the land with them. People began leaving, floating their fishing shacks and houses to shore with them. By 1915 the population was down to two: the lighthouse keeper and a watchman guarding the oyster beds. In 1942 the island disappeared completely. Now, it's only visible during very low tides from a boat, or from Great Beach Hill on Great Island. You can see some of the boulders from the riprap wall that was built to try to keep the sea out.