This day in 1949, the Soviets tested their first nuclear device, codenamed “First Lightning.” The 20 kiloton bomb was dropped in a remote region of Kazakhstan and detonated over a model town filled with empty buildings and animals, placed to measure the effects of the bomb on a city populated by mammals.

The development of nuclear weapons by the Soviets (research speeded along by the espionage of Klaus Fuchs, a German-born physicist involved in the US nuclear weapons project) removed the United States from supremacy in the nuclear arms race but fueled the development of “bigger and better” hydrogen based weapons that continues (although in modified form) even today.

Stephen Younger, the Associate Laboratory Director for Nuclear Weapons at the Los Alamos National Laboratory writes this regarding the effect of nuclear weapons in the world:

Nuclear weapons played a pivotal role in international security during the latter half of the twentieth century. Despite rapid increases munications, transportation, and weapons technology, there has been no large-scale strategic conflict since the Second World War. Nuclear weapons, as the most destructive instruments ever invented, had a stabilizing effect on superpower relations by making any conflict unacceptably costly. However, geopolitical change and the evolution of military technology suggest that position of our nuclear forces and our strategy for their employment may be different in the twenty-first century. The time is right for a fundamental rethinking of our expectations and requirements for these unique weapons.

For more information about the post-Cold War state of the arms race, read Stephen Younger’s paper “Nuclear Weapons in the Twenty-First Century.”