The Soviet Union has abandoned a top-secret bioweapon testing ground, Vozrozhdeniya Island, in the Aral Sea, along the Uzbekistan-Kazakhstan border, 34 years after it was abandoned. The island, which was home to 1,500 people, tested weapons that used plague, smallpox, and anthrax for decades. Despite being abandoned in the early 1990s, the U.S. and Uzbekistan did not officially decontaminate the site until 2002. The remaining residents of Kantubek, which once held 1,000 people, were left dwindling as the Soviet Union collapsed. The site was also used to test diseases such as plague and smallpox.