Cold War Discovery Center Opens in Dayton

From 1948 to 2003, Miamisburg’s Mound Laboratory carried out work so closely guarded that some of what it did remains secret to this day. The facility grew out of the World War II-era Dayton Project (part of the Manhattan Project), which turned sites ranging from a warehouse to a playhouse into labs that made the trigger used in the Trinity Project’s test “gadget” and the Fat Man atomic bomb dropped on Nagasaki, Japan, on Aug. 9, 1945.

Carillon Historical Park unveiled its new Mound Cold War Discovery Center on Feb. 26, 2026. The permanent exhibition honors the city’s scientific contributions to the Manhattan Project and the work of Mound Laboratory. A collaboration between Dayton History, The U.S. Department of Energy, Mound Development Corp. and the Mound Science and Energy Museum Association, the Discovery Center houses artifacts, photographs and firsthand stories from Mound Laboratory, which was instrumental in shaping the Cold War, the Nuclear Age and the Space Race.

Charles A. Thomas, head of the Dayton Project, deputy to Robert Oppenheimer and the operator of Mound Laboratory, was awarded the Medal of Merit by President Harry S. Truman in 1946. The new exhibition includes an animatronic version of Thomas, who shares information about the laboratory and its role in United States history with Carillon Historical Park visitors.

“The Mound operated only 8 miles southwest of Carillon Park," Brady Kress, president & CEO of Dayton History, said in a Feb. 27, 2026, press release. "Our community has long been a powerhouse of research, innovation and manufacturing. Over 75 years ago, Col. Edward A. Deeds founded Carillon Park to share the region's stories of ingenuity with the world. The Mound story fits perfectly into that mission.”

For more information, visit daytonhistory.org.

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