Key dates in the collapse of communism across Eastern Europe in 1989:

— June 4: Poland holds first partially free elections in four decades; Solidarity-led opposition wins all but one freely contested seat in parliament.

— August: Tens of thousands of East Germans swamp West German diplomatic missions in East Berlin, Czechoslovakia and Hungary seeking asylum.

— Aug. 24: In Poland, longtime Solidarity adviser Tadeusz Mazowiecki becomes Soviet bloc's first noncommunist prime minister.

— Sept. 11: Hungary opens its border with the West to East German refugees.

— Oct. 7: During visit to East Berlin, Soviet leader Mikhail Gorbachev indirectly urges reform; thousands demonstrate against East German regime in first of series of protests that grow to rally of 1 million people Nov. 4.

— Nov. 7-8: East Germany's ruling Politburo resigns.

— Nov. 9: Berlin Wall falls: Border between East and West Germany opens.

— Nov. 17: Students clash with police, starting Czechoslovakia's "Velvet Revolution."

— Dec. 17: Romanian police fire at protesters; dictator Nicolae Ceausescu and wife try to flee uprising five days later and are executed Christmas Day.

— Dec. 29: Communist rule ends in Czechoslovakia; dissident Vaclav Havel elected president.

1990:

— Oct. 3: Germany is reunited.

— Dec. 9: Lech Walesa wins Poland's first popular presidential election.