Basically the cold war was an ideological conflict between Russia (communist) and the USA (democracy) which emerged after the end of WWII when Germany split into East and West (communist and democratic respectively). Each superpower thought that they were right, and both had nuclear weapons, which prevented a full-scale fight, or a "hot" war, as it would lead to the destruction of the world. Instead both sides took part in a series of different conlicts, such as the space race, and the war in Vietnam (with each side backing half of the Vietnamese people who were carrying out their own little civil war). Ultimately (and eventually - after a lot of near-misses with the future of the planet) democracy won by default, as communism failed (although the Americans lost the Vietnamese war). Germany was reunited, and a direct line was installed between the White House and the Kremlin to prevent anything that terrible ever happening again.