Things we believed during the Cold War that ended up being wrong

The end of Communism would mean the end of history
Francis Fukuyama is famous for a single prediction. In 1989, he announced we'd reached the end of history. The Cold War was on the brink of ending and American geopolitical might seemed assured. Facing this generational shift, Fukuyama wrote (quoted here via The Guardian): "What we may be witnessing is not just the end of the Cold War, or the passing of a particular period of post-war history, but the end of history as such: that is, the end point of mankind's ideological evolution and the universalization of Western liberal democracy as the final form of human government."