Russia and Ukraine became founding members of the Soviet Union.

Millions died, mainly ethnic Ukrainians, in a man-made famine during Stalin's collectivization campaign, known as the Holodomor.

Western Ukraine was annexed by the Soviet Union under the terms of the Nazi-Soviet Pact.

Ukraine suffered significant wartime devastation as Nazis occupied the country. More than five million Ukrainians died fighting Nazi Germany, and most of Ukraine's 1.5 million Jews were killed by the Nazis.