A number of scientists associated with the Manhattan Project were eventually investigated by the House Un-American Activities Committee.

Between April 1945 and July 1947, eighteen subjects were injected with plutonium, six with uranium, five with polonium, and at least one with americium in order to better understand the effects of radioactive materials on the human body.

In January 1950, President Truman made the controversial decision to continue and intensify research and production of thermonuclear weapons.

India tested its first atomic bomb in 1974 but did not develop a significant nuclear arsenal until more than two decades later.

How to separate the much more potent U-235 from its abundant relative, U-238 consumed thousands of hours and millions of dollars.

Israel is widely believed to possess nuclear weapons, but has never confirmed the existence of its nuclear program.

Japan initiated multiple small efforts to pursue an atomic bomb, but all were unsuccessful.

On November 3, 1944, Japan released fusen bakudan, or balloon bombs, into the Pacific jet stream. Japan’s latest weapon, the balloon bombs were intended to cause damage and spread panic in the continental United States.

The War of the Pacific against Imperial Japan was marked by episodes of mass suicides by Japanese soldiers and civilians, notably in Saipan and Okinawa.