AHistoryIndependent states
Semipalatinsk Test Site (1949–1991)
The USSR's main nuclear test site, where 456 explosions were carried out; it was closed on 29 August 1991.
On 29 August 1949 the first Soviet atomic bomb was detonated on the steppe near Semey (Semipalatinsk). Over the next forty years 456 nuclear tests were carried out there, 116 of them above ground or in the air.
Radiation harmed the health of hundreds of thousands of local people, with rises in cancer, birth defects and other illnesses; nearby villagers lived for years unaware of the danger.
The Nevada–Semipalatinsk movement, founded in 1989 under Olzhas Suleimenov, brought thousands together, and on 29 August 1991 the site was closed by decree. In 2009 the UN declared 29 August the International Day against Nuclear Tests.
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Updated: October 2, 2026