12. The Russian Civil War, following on from the losses of the First World War, took the lives of a further 7,000,000 to 12,000,000 people
The Russian Civil War was a multi-factional conflict that chiefly took place between 1917 and 1922 to determine the future of the defunct Russian Empire. Beginning immediately after the Russian Revolutions of 1917, the primary combatants were the Red Army, led by Vladimir Lenin and fighting for the installation of Bolshevism, and the White Army, a broad tent of opposing forces including democrats, monarchists, and capitalists. In addition to these participants, several other independent armies fought for dominance and influence, as well as eight foreign nations which sought to determine the outcome in their respective favors.
With the Red Army ultimately victorious and creating the Soviet Union in 1923, the costs of the internal conflict were staggering. Estimates of the number people executed during the “Red Terror” by the Cheka, the Soviet secret police, ranged from the hundreds of thousands to in excess of one million; concurrently, the “White Terror” is believed to have been responsible for the deaths of 300,000 innocents, including 100,000 Jews in Ukraine. The remnants of the Cossacks were murdered or deported, with approximately half a million estimated to have been put to death. Meanwhile, several independence movements, sensing the weakness of Russian authority, took the occasion to become sovereign nations, including Finland, Estonia, Latvia, Lithuania, and Poland.