On December 8, 1991, the leaders of Russia, Ukraine, and Belarus declared that the Soviet Union had "ceased to exist." Twenty-five years later, we look back on some key milestones -- inside and outside the Soviet Union – on the road to its collapse.
End Of An Empire

1
June 1979: Pope John Paul II tours his native Poland, drawing the biggest crowds in the country’s history. He avoids directly criticizing the country’s communist rulers, but his carefully worded speeches on the "inalienable" rights of people help reawaken the spirit of resistance in Poland. Months later, Solidarity, a trade union with strongly anti-Soviet leadership, is founded in Gdansk and within a year has nearly 10 million members.

2
September 1983: Korean Air Lines Flight 007, en route from the United States to Seoul with 269 passengers and crew, drifts off course and into Soviet airspace. Soviet fighter jets are scrambled amid suspicions the intruder is a U.S. spy plane. After warning shots go unnoticed, Su-15 interceptor pilot Gennady Osipovich slams a heat-seeking missile into the Boeing 747. The shattered plane plunges into the Sea of Japan, killing all onboard.

3
March 1985: Mikhail Gorbachev, here greeting U.S. President Ronald Reagan, becomes general secretary of the Communist Party of the Soviet Union. The new leader promises a more open and democratic Soviet future. Such statements have been heard before and few expect change, but this time it’s for real.

4
1986: World oil prices crash, falling from $27 to below $10 a barrel. The U.S.S.R. can no longer afford to prop up the moribund economies of its satellite states.