Chicago Pile-1 Site A

Burial site of the world's first nuclear reactors in a Chicago nature reserve — a quiet, sobering landmark at the dawn of the atomic age.

Hidden in the Red Gate Woods nature reserve south of Chicago, Site A is one of the most consequential — and least visited — historic sites in the world. This is where the radioactive remains of Chicago Pile-1, 2, and 3 are buried: the world's first nuclear reactors, built as part of the Manhattan Project. On December 2, 1942, Enrico Fermi achieved the first self-sustaining nuclear chain reaction using Chicago Pile-1 beneath the stands at Stagg Field, University of Chicago. The reactors were later relocated here and eventually entombed underground. A modest commemorative plaque marks the spot, which remains under US Department of Energy oversight and carries a low residual radiation signature. A genuinely eerie place to stand and contemplate a turning point in history.