What seemed like a bizarre natural incident near the Aral Sea turned out to be a leak from Aralsk-7—a top-secret Soviet biological weapons facility. Known today as Plague Island, the site was used to develop weaponized smallpox, plague, anthrax, and other deadly pathogens in violation of international treaties.

The outbreak was quickly suppressed and hidden from the world, but the truth eventually emerged through declassified CIA reports and testimony from Soviet defector Ken Alibek.

This Cold War relic was once one of the most dangerous places on Earth—and almost no one knew it existed.