The photo to the left is one of MNN's 12 sinkholes, and is one sinkhole of many that have formed around the town of Picher, Oklahoma, a place the EPA has called the most toxic place in America.
At one time Picher was the world's largest producer of zinc and lead in the world. At its peak over 14,000 miners worked the mines and another 4,000 worked in mining services. The mines shut down in the closing years of the 1960s, and the companies pulled out. With the mines closed, pumping operations ceased and contaminated water filled the mines. The risk of mine collapses became a major threat, with one collapse in 1967 destroying nine homes. Eventually, contaminated water reached the surface, polluting the surface watershed. On top of that, the mines left behind 70 million tons of mine tailings, and 36 million tons of mill sand and sludge. The tailing piles were contaminated by lead dust, and wind would blow the dust into town leading Picher children to have elevated risk of learning disabilities and other problems. Before they knew better, the tailing mounds were used as sledding hills in the winter.
The area is now part of the Tar Creek Superfund site, and conditions were so bad that the town was ordered closed and all residents removed. Federal funds were used to buy out residents to allow them to relocate. In June of 2009 the last residents met to say goodbye to the town. Picher is now a ghost town, considered too toxic to inhabit.
Picher was featured in the PBS Independent Lens film The Creek Runs Red discussing the connection of the people and their desire to leave or stay in the city. It's nearly an hour long, but it's a good watch as it really shows the impact that the pollution has had on the town and how people will hold onto something, even as it dies in front of them.
And here's a drive-through of the now abandoned city of Picher. As the clip's commentator mentions, the residents left a lot behind; stores left their wares on the shelves do to contamination.