Chicago Pile-1

Chicago Pile-1 is a nuclear research site at the University of Chicago in Illinois. The construction consisted of stacked graphite blocks and uranium pieces arranged within a wooden frame beneath the stands of a sports field.

In December 1942, a team led by Enrico Fermi achieved the first controlled nuclear chain reaction in history. The experiment took place in a converted squash court and opened the path toward atomic energy development.

The facility became part of the Manhattan Project, bringing together international scientists who collaborated despite wartime restrictions and security classifications.

The original reactor no longer exists, but a plaque and monument on the university campus mark the historic experiment. Visitors can access the grounds freely and read the information panels.

The experiment was conducted in a room beneath spectator stands because no other laboratory space was available for the project. The setup operated without concrete shielding, which today would be considered completely inadequate for radiation protection.