Casings for the "Thin Man" plutonium gun design weapons, ca. 1945.

Casings for the "Thin Man" plutonium gun design weapons being developed during the Manhattan Project as part of Project Alberta at Wendover Field, Utah (additional "Fat Man" test casings can be seen in the background as well), circa 1945. Foto: US Government employee/United States Department of Energy, Quelle: Wikimedia Commons, Lizenz: Public Domain