What are the main event which lead to the collapsed of soviet union ( the main point )

Gorbachev's decision to loosen the Soviet yoke on the countries of Eastern Europe created an independent, democratic momentum that led to the collapse of the Berlin Wall in November 1989, and then the overthrow of Communist rule throughout Eastern Europe.

Explanation:

for more info refer to this site

https://history.state.gov/milestones/1989-1992/collapse-soviet-union

in the 1950s, country music came into its own before rock-n-roll took off in the 60s while jazz and classical music continued to innovate