Giant domino pieces installed along a stretch of the Berlin Wall's original path are seen at Brandenburg Gate in Berlin on, Nov. 9, during celebrations marking the 20th anniversary of the fall of the Berlin Wall. AP/Wolfgang Rattay

BERLIN – Ulrich Sauff and his wife stared at the mammoth domino pieces marking the path where the Berlin Wall once stood and reminisced about life in the barrier's shadow.

"It was like a prison," said Sauff, 73, who lived on the Western side of the wall. "For us 'Wessis,' the few kilometers from our old home to our new home (in the East) was unthinkable."

The Sauffs were among those who gathered Monday to celebrate 20 years of unity, marking the day the wall came down. Thousands cheered as 1,000 colorfully decorated dominoes along a mile-long route were toppled to symbolize both the moment the wall came crashing down and the resulting fall of communist governments in Eastern Europe.

It was the finale to a day of memorial services, speeches and events that attracted leaders from around the world, including former Soviet leader Mikhail Gorbachev.