On This Day In 1939, Einstein Told President Roosevelt To Build A Nuke Before Hitler

74 years ago today, in 1939, Albert Einstein wrote a remarkable letter to President Franklin D. Roosevelt about the need for the United States to compete with Germany in developing nuclear technology.

In it, Einstein highlights recent experiments in uranium.

"It is conceivable — though much less certain — that extremely powerful bombs of a new type may thus be constructed," he wrote.

Einstein encourages Roosevelt to strengthen communication "between the Administration and the group of physicists working on chain reactions in America."

Of course, the United States beat Germany, and the rest of the world, in acquiring nuclear weaponry, and went on to wield the atomic bomb against the Japanese cities of Hiroshima and Nagasaki.

Notably, the only country ever to do so in battle.