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Nineteen eighty-nine was the biggest year in world history since 1945. In international politics, 1989 changed everything. It led to the end of communism in Europe, of the Soviet Union, the cold war and the short 20th century. It opened the door to German unification, a historically unprecedented European Union stretching from Lisbon to Tallinn, the enlargement of Nato, two decades of American supremacy, globalisation, and the rise of Asia. The one thing it did not change was human nature.

In 1989, Europeans proposed a new model of non-violent, velvet revolution, challenging the violent example of 1789, which for two centuries had been what most people thought of as "revolution". Instead of Jacobins and the guillotine, they offered people power and negotiations at a round...