Rumors of what had happened in Mayak reached the West, but Chelyabinsk-40 was among the most fiercely guarded military locations in the USSR. The Soviet government refused to acknowledge its very existence, let alone that anything might have happened there. The CIA resorted to sending high-altitude U-2 spy planes to photograph the area. It was on the second of these missions, in May 1960, that Francis Gary Powers’s aircraft was shot down by a Soviet SA-2 surface-to-air missile, in what became one of the defining events of the Cold War.
