Imagine an American-centric, worst nightmare portrayal of the peak of the Cold War. It probably looks a little like hazard-suited Soviets, tinkering with terrifying diseases we long thought were extinct. And that probably looks a lot like Vozrozhdeniye Island just a few decades ago.

In 1948, the Soviets opened up a tiny laboratory on the island in the Aral Sea. Before the Aral Sea began to disappear, top-secret work was conducted by teams of scientists researching the weaponization of some of the most deadly diseases humankind has ever known. Over the next 40 years, the Soviets conducted open air tests on smallpox, anthrax and the bubonic plague on the island, hoping its isolation would keep the deadly illnesses from escaping.

After the fall of the Soviet Union, the island facility was abandoned, and the remnants of the weaponized diseases were buried quickly. As the island slowly became desert and the sea slowly disappeared due to Soviet irrigation projects, the once isolated island became a part of the mainland.

Over concerns that deadly pathogens could still be alive on the island, a team of Russians went to the once active facility site to decontaminate the land. According to their report in 2001, everything was clear. However, a conflicting report in 2005 showed that there were still remnants of the facility including test tubes for conducting experiments on animals, which preserved the chance of deadly diseases such as anthrax still being present in the area.