Chernobyl: Chernobyl was a nuclear disaster which killed 31 people and caused a lot of radiation as well as money. This incident happened within the Ukraine. The event was under direct control from the Soviet Union, which explains why the incident occurred. The soviet union was ultimately the reason for this incident.
Perestroika: Perestroika was the policy which stated that Soviet citizens could protest and complain about economic problems and not have any consequences after. This policy was under jurisdiction of Gorbachev, the new Soviet leader. The main purpose of Perestroika was to reconstruct the Soviet Union's economy as well as government. This happened so that Communism would not be dispelled, but rather strengthen it and make it more efficient.
Democratization: Democratization was a huge deal in the Soviet Union. It was the first time in history that the Soviet society had a right to vote and pick out who they wanted to win the election. Gorbachev said that for the economy to thrive, that they would have to loosen up; they did so by having elections.
Years of Miracles: In the year of miracles, Hungary was inspired by Poland, which led them to build a new constitution which assured free parliamentary elections. In this year, radical reformers took over a communist party, dispelled their leaders, and later dissolved it. Also, a year later, a non-communist government was set in power.
Fall of the Berlin Wall: East Germany demanded the right to travel freely and to have free elections, Honecker, leader of Germany stated that reforms were unnecessary and ordered police to break up a demonstration in Leipzig, but the police refused. Honecker lost his power and resigned. After, Krenz came into power and attempted to stabilize Communism. Krenz decided to open up Berlin wall and let east Germany into the West. Krenz had to resign due to widespread corruption being discovered, thus ending the East Communist party once and for all.
Collapse of the Soviet Union: All 15 unions declared independence from the Soviets which ended the Soviet Union. This happening showed that the Union had lost its power and through the power of Boris Yeltsin, it was seen as unconstitutional. This was no longer in relations with the Soviets, for the Union had dismantled, and peace was reached in all of Easter Europe.