It was the second worst nuclear disaster in history after Chernobyl. It blew a 160-ton concrete lid into the sky, contaminated up to 20,000 square kilometers, and forced 10,000 people from their homes. Yet for decades, almost no one in the world even knew it happened.

This episode dives into the 1957 Kyshtym disaster at the Soviet Mayak plutonium plant, a chilling story of the Cold War arms race, staggering environmental negligence, and extreme secrecy. The mechanics of how the explosion was erased from the historical record are as fascinating and terrifying as the blast itself.

• How a closed city that didn't appear on any map produced plutonium at breakneck speed with safety as an afterthought
• The early dumping of radioactive waste straight into the Techa River and shallow Lake Karachay
• Why a failed cooling system ...