The Cold War was a period of geopolitical tension between the Soviet Union and its satellite states and the United States with its allies following World War II. The allies were concerned with the brutal leadership of Joseph Stalin as well as the spread of communism. Confrontations included the Berlin Airlift, the Berlin Wall, the Korean Conflict, the Cuban Missile Crisis, the Pueblo Incident, the bombing in Lebanon, the nuclear arms race, and the space race. The fall of the Berlin Wall on November 9, 1989 was a pivotal event in world history that marked the collapse of the Iron Curtain and the start of the fall of Communism. The Cold War ended with the dissolution of the Soviet Union in 1991.