Change:-5 Reason: France and China acquire and test nuclear weapons ( 1960 and 1964 respectively), wars rage on in the Middle East, Indian subcontinent, and Vietnam . Year: 1969 Mins Left:10 Time:11:50 Change:+3 Reason:The U.S. Senate ratifies the Nuclear Non-Proliferation Treaty . Year: 1972 Mins Left:12 Time:11:48 Change:+2 Reason:The United States