That 70's Sex Show

American Swing, the documentary, directed by Jon Hart and Matthew Kaufman, uses the people who were there to tell the story of Plato’s Retreat.
Over the course of three and a half years, the directors managed to assemble an archive of pungent footage shot inside the club. We see the fabled orgy room (wall-to-wall mattresses), the proletarian buffet ("disgusting," one regular recalls) and the appalling pool, a chlorine soup thickened with the byproducts of aquatic coupling.
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Swingin’ Grandmas Recall Seventies Sex Club