Kyshtym disaster

At the same time as the construction of the Mayak complex, work was being carried out on a workers' settlement - the town of Ozyorsk.

An excerpt from the article 42 facts about Kyshtym disaster

Initially, the town was called Base-10 (until 1954), Chelyabinsk-40 (until 1966), and Chelyabinsk-65 (until 1994) and was not visible on maps of the USSR. In 1954 it was granted city rights, and the official name of Ozyorsk was established in 1994.