The Cold War
Onset. The World War II Allied victors (UK, USA, USSR) met at the Potsdam Conference in the summer of 1945 to plan the post war political structure. The plan, which left Berlin isolated in Communist controlled territory, was unworkable and ushered in the Cold War. Over the next 45 years or so, this war became hot in Korea, Vietnam, Afghanistan, and other spots in the world where the world powers got involved in regional wars, revolutions, coups d'état, and uprisings. The Hungarian Uprising of 1956 demonstrated that the USSR was willing to brutally put down any opposition to communist rule. Again, the USSR invaded Czechoslovakia and put down the Prague Spring Uprising in 1968.
End. An icon of the Cold War was the Berlin Wall, built by Communist East Germany in 1961 as an "anti-Fascist protection wall." It was thoroughly despised but lasted 28 years. It finally Fell in 1989. The Soviet Union broke apart shortly thereafter, marking the end of the Cold War.