Decades before Chernobyl, the Soviet Union faced a nuclear catastrophe so severe that they kept it hidden from the world for nearly 20 years. This was the Kyshtym Disaster of 1957. It happened at the Mayak plutonium production plant. A cooling system in a massive underground tank containing liquid radioactive waste failed. As the liquid evaporated, the waste overheated, eventually triggering a powerful chemical explosion with the force of roughly 70 tons of TNT. The blast was so intense it blew