Chatham, MA is protected from the open ocean by a narrow sandbar.  Years ago there were 13 cottages on the sandbar that were accessible by an off road vehicle trail.  The off road vehicle trail was cut off by a an opening in the sand bar (the North cut).  Today there are two cottages remaining.  When there were three cottages remaining the main section of the Dune Shack was their outhouse.  During a storm the outhouse floated to its current position.  The owner of the outhouse wanted to retrieve the outhouse but had to wait until piping plover hatching season ended.  A few weeks after the storm the plovers had hatched so the owner went to recover the outhouse but the outhouse had been stood up and the structure had been built by people who had found driftwood on the beach.  The dune shack is now maintained by locals and the flag is changed when it becomes tattered. Beach erosion has put the dune shack in a precarious position on the water's edge.  To see the dune shack go to Chatham Lighthouse, 1 Main Street, Chatham, MA.  Across from the lighthouse are stairs to the beach.  Walk to the water and turn right.  The dune shack is about a third of a mile down the beach.  You can also follow the dune shack of Facebook.  It's page is "Occupy Chatham".