10 Nuclear Disasters That Made the World Stand Still ... In what was once the Soviet Union, Kyshtym was built in an attempt to match the work already carried out by American researchers.

In 1957, a massive nuclear accident took place at the top ... and details of the devastating legacy of what is now known as the 'Kyshtym disaster' are still only just becoming clear today.

IFL Science reports that Karachay is "the most radioactive lake on Earth". Additionally, its waters are so highly irradiated that spending just an hour sunbathing on its shores could prove fatal.