Short answers, pulled from the story.
The Solidarity trade union formed on the 14th of August 1980 following a massive general strike at the Lenin Shipyard in Gdańsk. This independent organization grew to include ten million members by 1981 and became the first of its kind in the Eastern Bloc.
Mikhail Gorbachev introduced glasnost for greater freedom of speech and perestroika for economic restructuring after assuming power in 1985. These policies allowed for multi-candidate elections by spring 1989 and implicitly renounced military force against Warsaw Pact nations in July 1989.
Over 1,000 people died during the Romanian Revolution which began on the 16th of December 1989 in Timișoara. The violence included one hundred children with the youngest victim being just one month old before Nicolae Ceaușescu was executed on Christmas Day.
The Berlin Wall fell on the 9th of November 1989 when regime spokesman Günter Schabowski announced that travel restrictions were lifted immediately. Thousands of East Germans flooded the border crossing and citizens tore down sections of the wall using hammers and chisels.
The Supreme Soviet legally dissolved itself on the 25th of December 1991 after Mikhail Gorbachev resigned as Soviet president. This event followed the Belavezha Accords signed by Russian President Boris Yeltsin and leaders from Ukraine and Belarus on the 8th of December 1991.