The program was set in motion by Soviet leader Mikhail Gorbachev to fight economic stagnation by scaling back government power.
His efforts impressed Pres. Ronald Reagan, leading the two men to strike up a friendship. It began with their first meeting at a summit in Geneva on Nov. 19, 1985.
Depending on their national and political loyalties, historians give Gorbachev either the credit or blame for beginning the process that ultimately led to the downfall of the Soviet Union.