- 1905: Bloody Sunday: A peaceful demonstration by workers in St. Petersburg is met with violence from the tsar's troops, leading to the deaths of hundreds.
- 1906: The First Russian Revolution: A wave of strikes and demonstrations leads to the establishment of a parliament, the Duma.
- 1914: Russia enters World War I on the side of the Allies.
1917–1922: The Russian Revolution and Civil War
- 1917: The February Revolution: Tsar Nicholas II is overthrown, and a provisional government is established.
- 1917: The October Revolution: The Bolsheviks, led by Vladimir Lenin, seize power in a coup.
- 1918–1921: The Russian Civil War: The Bolsheviks fight a bloody war against various anti-communist forces.
- 1922: The Union of Soviet Socialist Republics (USSR) is formed.
1922–1941: The Soviet Union Under Stalin
- 1924: Lenin dies, and Joseph Stalin takes over as leader of the Soviet Union.
- 1928–1933: The Five-Year Plans: Stalin's ambitious industrialization program.
- 1932–1933: The Great Famine: A massive famine kills millions of Ukrainians.
- 1937–1938: The Great Purge: Stalin's campaign of political repression.
1941–1945: World War II
- 1941: Nazi Germany invades the Soviet Union, beginning the Great Patriotic War.
- 1942: The Battle of Stalingrad: A major turning point in the war, in which the Soviet Union defeats the German army.
- 1945: The Soviet Union defeats Nazi Germany, and the war ends.
1945–1950: The Post-War Soviet Union
- 1945: The Soviet Union emerges from the war as a superpower.
- 1947: The Cold War begins as the Soviet Union and the United States compete for global dominance.
- 1949: The Soviet Union tests its first atomic bomb.
- 1950: The Korean War begins.