Leveling a mountain for coal in Appalachia. American mining companies get an exemption to national laws requiring them to return the land to its natural state after mining is finished. This is one of the poorest regions in the U.S., and mountain top mining is seen as a source of much-needed jobs. Here the mountain tops are blown off and dumped into river valleys to leave sprawling infertile mesas in what were once diverse temperate forests. Seven units of overburden are moved for every unit of coal extracted, which makes this marginally profitable economic activity have a huge environmental cost.