Chicago Pile One, Plot M: The Buried Atom

Beneath the ground near this marker lies radioactive material from one of the most consequential experiments in history. Chicago Pile One, the world's first artificial nuclear reactor, achieved the first controlled self-sustaining nuclear chain reaction on December second, nineteen forty-two, under the stands of a University of Chicago football stadium. After the war, the reactor's remains were buried at nearby Site A, and low-level waste from the same research went into Plot M.

The Department of Energy marked the site in nineteen seventy-eight with a blunt warning not to dig, with corner markers one hundred feet from the center. The buried material poses no surface danger, but it will remain radioactive for thousands of years. This quiet forest preserve corner in suburban Chicago is a permanent artifact of the atomic age.