Babado USA on Instagram: "The “Demon Core” was a plutonium sphere weighing about 6.2 kg, used by the Manhattan Project, the American nuclear weapons development program, after the end of World War II. This core became famous (or infamous) for being involved in two fatal criticality accidents in 1945 and 1946 at the Los Alamos National Laboratory in the United States. The first incident, on August 21, 1945, involved physicist Harry Daghlian Jr., who was stacking neutron-reflecting blocks around t