Chicago Pile No 1, 1942.
© Science Museum / Science & Society Picture Library
Model (scale 1:8). On 2nd December 1942, Enrico Fermi (1901-1954) and a team of scientists in Chicago achieved the first self-sustaining chain reaction, in Chicago Pile No 1, the world's first nuclear reactor. It was built in a squash court at the University of Chicago and was a pile of graphite blocks containing lumps of uranium, in a wooden framework. This reactor was built as part of the Manhattan Project to construct the first atomic weapons.