Research into the development of nuclear weapons was initially undertaken during World War II by the United States ( in cooperation with the United Kingdom and Canada ) , Germany , Japan , and the USSR . The United States was the first and is the only country to have used a nuclear weapon in war , when it used two bombs against Japan in August 1945 . After surrendering to end the war , Germany and Japan ceased to be involved in any nuclear weapon research . In August 1949 , the USSR tested a nuclear weapon , becoming the second country to detonate a nuclear bomb . The United Kingdom first tested a nuclear weapon in October 1952 . France first tested a nuclear weapon in 1960 . The People 's Republic of China detonated a nuclear weapon in 1964 . India conducted its first nuclear test in 1974 , which prompted Pakistan to develop its own nuclear program and , when India conducted a second series of nuclear tests in 1998 , Pakistan followed with a series of tests of its own . In 2006 , North Korea conducted its first nuclear test
first nuclear test
2006 North Korean nuclear test
Nuclear proliferation