What was the Cold War and which two countries were opposed to one another during it?

The Cold War was a prolonged period of geopolitical tension and ideological conflict that lasted from the late 1940s until the early 1990s, primarily between the United States and the Soviet Union. It was characterized by competition in military power, economic systems, and political influence, without direct large-scale fighting between the two superpowers. Instead, it involved proxy wars, espionage, and a nuclear arms race, shaping global alliances and conflicts. The Cold War ended with the dissolution of the Soviet Union in 1991.