August 18, 1991: A small plane crashes in the southeastern portion of the Ukrainian SSR, killing all five people on board. A later investigation cites engine failure as the cause of the crash.
August 20, 1991: The New Union Treaty is signed by the nine remaining republics in the Soviet Union. By the end of the year, the country will be known as the Union of Soviet Sovereign Republics. The new government is a confederation modeled after the American "states" system in which each republic is sovereign in its own right, but they are all united by a common currency, President, and legislature.
December 25, 1991: The New Union Treaty officially goes into effect, creating the Union of Soviet Sovereign Republics. The treaty also recognizes the independence of Georgia, Armenia, Moldova, Latvia, Lithuania, and Estonia.