The Cuban Missile Crisis of 1962 brought the U.S. and the Soviet Union close to nuclear war over
ASoviet nuclear missiles placed in Cuba
Bthe building of the Berlin Wall
Cthe border between North and South Korea
Dcontrol of the Panama Canal
Explanation
For 13 days the superpowers faced off until the USSR agreed to remove missiles from Cuba; it was the closest the Cold War came to nuclear war.