While the above image might appear to be rather placid, Lake Karachay was named the most polluted spot on Earth, according to a report by the Washington, D.C.-based Worldwatch Institute on nuclear waste. From 1951 to 1953, the Soviet Union used the lake as a dumping spot for all of the nuclear waste from their largest nuclear production facilities called Mayak.
In 1968, following a drought in the region, the wind carried radioactive dust away from the dried area of the lake, irradiating half a million people. According to Environmental Health Perspectives, "to help prevent such lethal airborne contamination, Russian engineers have been gradually covering Lake Karachay with stones and concrete blocks, a controversial remediation method. 'The stones help prevent the dust, but the weight also presses the sediments down and moves them closer to the groundwater,' says Thomas Nilsen, a researcher at the Bellona Foundation, 'It's a catch-22.'"
(Photo: Собственная работа/Wikimedia Commons)