During World War II, the USGS Military Geology Unit (MGU) played a critical role in national security by delivering vital terrain intelligence to support military strategy. Established on June 24, 1942, at the request of the U.S. Army Corps of Engineers, the MGU prepared terrain studies to meet urgent wartime priorities. This elite unit comprised 114 professionals—including 88 geologists, 11 soil scientists, and 15 other specialists, with 14 pioneering women among them. Among the remarkable women who served was Julia A. Gardner, a geologist who led the team known as "The Dungeon Gang". Gardner’s expertise was invaluable when Japanese balloon-borne incendiary bombs appeared on U.S. soil. By analyzing the tiny shells in the balloons' ballast sand, she pinpointed the exact beach in Japan used as the launch site. This critical intelligence directly informed defense strategies and showcased the power of geological science in protecting American soil. Beyond her wartime contributions, Gar...