The Cold War was deadly serious business, but it was also oftentimes bordering on the absurd. Not content with a bomb that can raze entire cities – and proving it out in Japan –  the U.S., quickly followed by the Soviet Union, got to work on a much more destructive model, using the fusion of hydrogen atoms. The fusion would release enormous amounts of heat and energy: whereas the atomic bombs dropped on Hiroshima and Nagasaki were measured in the range of 12-20,000 tons of TNT, the hydrogen bomb would be in the range of millions.

On this day, January 31, in 1950, President Truman announced the U.S. was taking the first steps towards the development of a hydrogen bomb. A lot of the groundwork had in fact already been laid, and within two short years, America had a working model of a hydrogen bomb.

A lot of the groundwork for the bomb’s development in the USSR was laid thanks to their far-reaching atomic spy network. The Russians had no fewer than four spies at various levels of hierarchy in Los Alamos during the formative years of the atomic program. Their intensive efforts to pass along secrets to the Russians allowed the communist country to match every breakthrough the U.S. made.