Robert Nobles and William Sturm were physicists at the University of Chicago’s Metallurgical Laboratory. They contributed to the creation of experimental nuclear reactors, including the world’s first heavy water reactor, the Chicago Pile-3. In this interview with author Stephane Groueff, Sturm and Noble discuss the security of the bomb project in Chicago, and the movement of scientists between the different sites. They also recall Eugene Wigner’s graciousness, Leo Szilard’s excitability, and Walter Zinn and Enrico Fermi’s leadership styles. They praise the scientific community for its embrace of international cooperation and respect.