The first nuclear reactor, explained

In 1942, the Manhattan Project needed to create a chain reaction-a crucial step towards proving that it would be possible to make an atomic bomb. They achieved this first sustained chain reaction , the first created by humans, on Dec. 2, 1942, in a squash court at the University of Chicago. Nicknamed "Chicago Pile-1," the world's first nuclear reactor kicked off the Atomic Age and has a complicated legacy, including the rise of both nuclear energy and nuclear weapons. Jump to sections: How did the first nuclear reactor come to be? What did the reactor look like? How did the reactor work? What happened on the day of the first chain reaction? What happened to the reactor afterward? How did the reactor lead to the first atomic bomb? What was the legacy of the first nuclear reactor? Atomic bombs Nuclear energy Chemistry and biology Science Medicine Can you visit it? - How did the first nuclear reactor come to be? . As physicists came closer to understanding the nature of the atom in the 1930s, it became increasingly clear that a great deal of energy could be released by splitting atoms. In 1939, Albert Einstein and Leo Szilard co-wrote a letter to U.S. President Roosevelt, explaining that the discovery could be made into a powerful weapon, and that Nazi scientists likely had the tools to do so.