Travel 3,400 miles off the Chilean coastline to the middle of the Pacific Ocean, and you’ll see where the world has been hiding its dirty little secret. Henderson Island, one of the four Pitcairn Islands, is a UNESCO World Heritage Site that is almost never visited by people. There are no human inhabitants, no industrial facilities. The nearest settlement is on an island 71 miles away with a total population of 40. In fact, the Pitcairns are so small, their government is based in New Zealand, over 3,000 miles to the southwest. Yet despite its extreme isolation, this tiny, uninhabited island is home to the most polluted beach on the planet.