In August 1991, communist hardliners tried a death-or-glory tactic to save the Soviet Union - seizing power by force. Their coup failed and the Soviet Union was dead within months.
But the chain of events leading to the collapse was set in motion six years earlier, when Politburo member Mikhail Gorbachev became Soviet leader. He was only the sixth leader since the USSR's birth in 1922 - but his actions were to make him the last.
Click on the dates above to follow the key developments, and to see and hear what was happening, as BBC News Online charts the fall of an empire.