The "Gadget" detonated at the "Trinity" test in July 1945. Behind the bomb is Norris Bradbury, who would succeed Oppenheimer as the director of Los Alamos after the war, and Boyce McDaniel, a nuclear physicist, is on the right. This photo is not quite as rare as the others here, but most of the reproductions of it are extremely washed out. I've tried to manually get higher dynamic range by adjusting the levels of different areas (e.g., the sky, the people, the bomb) separately. I love the expressions on Bradbury and McDaniel's faces, and the way this photo makes clear how ad hoc and "messy" the first atomic bombs were—a mess of wires and rivets.
Los Alamos National Laboratory, LA-UR-06-1005 (TR-297).