Nestled deep in Russia’s Ural Mountains, close to the modern Kazakhstan border, Lake Karachay falls within the Mayak Production Association, one of the country’s largest (and leakiest) nuclear facilities. Built in the 1940s, immediately after World War II, Mayak was one of Russia’s most important nuclear weapons factories and was inaccessible to foreigners for 45 years. But when President Boris Yeltsin signed a decree in 1992 that opened up the area, visiting scientists who gained access immediately declared it the most polluted area on the planet. It seems that in its long period of obscurity, Mayak was the site of numerous nuclear-related accidents, some almost as devastating as the Chernobyl meltdown.