One year ago, as Americans sat on curbsides to watch parades, walked through cemeteries to place wreaths and flowers on graves and flinched at the roar of 21-gun salutes, there was no way they could have anticipated the scope and magnitude of events about to shake the world.

Within a week of the last Memorial Day observance, student demonstrations in China flared into open defiance of the communist government. A copy of the Statue of Liberty was erected in Beijing’s Tiananmen Square. On June 3, the voices of protest were silenced, hundreds of them permanently, by tanks and machine guns.

The Chinese leadership massacred its own people in a desperate effort to cling to power. It was the bloodiest of a series of confrontations between entrenched communist leadership and their people that seemed to explode in the aftermath of visits by Mikhail Gorbachev. The Soviet leader unleashed across Asia and Eastern Europe a whirlwind by acknowledging the intellectual, philosophical and economic poverty of the communist system.

With the speed of the Blitzkrieg 50 years earlier, Czechoslovakia, Poland and Yugoslavia quickly fell. Impregnable bastions of Leninism in East Germany and Romania toppled like dominoes. The Baltic Republics, Lithuania, Estonia and Latvia, in a courageous and stirring rendition of the American experience two centuries earlier, issued declarations of their independence from the Soviet Union.

None of this could be foreseen a year ago. The degree and the speed of such profound change. The setting in motion of events that could not be called back. The withering away in days of what more than half a century of communist domination had imposed.

Late on Memorial Day last year, Americans could not know that they were observing the twilight of a world power and were within weeks of witnessing the slow disintegration of an empire, the tearing down of political and physical barriers that had imprisoned human beings, but not the human spirit.

They couldn’t know that the coming year would produce an important Memorial Day monument, significant not because it is standing, but because it crumbled.

The young Berliner in the photograph is working determinedly with hammer and chisel, making one person’s contribution to a massive undertaking, the tearing down of the Berlin Wall, the wall of shame, a structure that symbolized an evil that three generations of Americans fought against, a noble cause in which many died.

The fight against communism went on for 40 years. Sacrifices were made in open warfare in Korea and Vietnam and in accidents aboard ship or in the field that claimed the lives of servicemen. It was the consequence of an enemy’s onetime belief that world domination was possible. It was the price of vigilance. The cost of freedom. It should be remembered on this Memorial Day.