This decade saw many global events that increased tensions. The U-2 incident in 1960 undermined a potential nuclear test ban treaty between the US and Soviet Union. This contributed to John F. Kennedy being elected on a promise of being tougher on the Russians. Cuba's revolution brought Fidel Castro to power. China tested its first nuclear bomb and separated from the Soviet Union. Kennedy was president during the failed Bay of Pigs invasion and construction of the Berlin Wall. Yuri Gagarin became the first person in space. Kennedy was assassinated in 1963.