The Cold War.

The Cold War was a political and ideological conflict between the United States and the Soviet Union, which lasted from the end of World War II in 1945 until the collapse of the Soviet Union in 1991. It was called a "cold" war because it never escalated into direct military conflict between the two superpowers, but it was characterized by a constant state of tension, propaganda, espionage, and proxy wars fought by the United States and the Soviet Union in various parts of the world. The Cold War began as a result of the opposing ideologies of capitalism and communism. The United States and its Western allies believed in the capitalist system, which emphasizes private property, free markets, and individual rights, while the Soviet Union and its allies believed in communism, which emphasizes collective ownership, central planning, and equality. The two superpowers became increasingly suspicious of each other's intentions and actions, and a climate of fear and distrust permeated international relations. The most notable events of the Cold War include the Korean War, the Vietnam War, the Cuban Missile Crisis, the construction of the Berlin Wall, and the arms race between the United States and the Soviet Union. The Cold War ended with the collapse of the Soviet Union in 1991, which marked the victory of the United States and its allies in the ideological and geopolitical struggle.