Two decades ago on Monday, the world watched in awe as Germans poured by the millions into the streets of Berlin, both east and west. They tore down one of history’s great monuments of human enslavement, and in so doing, the German people not only reunited with their fellow brothers and sisters after 28 painful years apart; they also gave birth to the promise of a Europe whole, free and at peace.

The fall of the Berlin Wall, and the collapse of communism that followed, was the work of many hands, eastern and western, European and American, soldiers and statesmen. But perhaps the most profound blow against totalitarianism was struck by an idea: the universal appeal of human rights – life and liberty, the protection of property, and rule by the consent of the governed. The west’s support for these values, and for all who kept faith with them behind the Iron Curtain, helped to win the cold war, and 20 years later, there is much we can learn from this experience.