sentences:  Sandstone Retreat
  
  Sandstone Retreat, officially the Sandstone Foundation for Community Systems Research, was a clothing-optional, open sexuality resort for swingers located at Sandstone Ranch, a estate in the Santa Monica Mountains overlooking Malibu and the Pacific Ocean.The community’s beginnings are based on the philosophical ideals of John (July 31, 1932 – March 24, 2013) and Barbara Williamson.