Top 5 Biggest Nuclear Weapons Tests

These Are The 5 Largest Nuclear Detonations in History. Since the first nuclear test on 15 July 1945, there have been over 2,051 other nuclear weapons tests around the world. Within 20 years, the US and USSR tested nuclear weapons larger than 10 megatons, or 10 million tons of TNT. For scale, these weapons were at least 500 times as strong as the first atomic bomb. To put the size of history’s largest nuclear blasts to scale, we have used Alex Wellerstein’s Nukemap, a tool for visualizing the terrifying real-world impact of a nuclear explosion.