Lenin, whose use of power in the Soviet Union, which he created and whose influence in the wider world was wholly for the bad, is undoubtedly the century's dominant figure. The ideas of Karl Marx were of little more than philosophical importance until 1917, when Lenin applied those ideas with revolutionary force and established the Bolshevik Party throughout the government. Bolshevik Russia became an example to Marxist revolutionaries everywhere and energized nationalist reactionaries, of whom the most important was Adolf Hitler. Hitler's ideological war on the Soviet Union devastated Europe. After Lenin's death, his followers in Europe, Asia and Africa created other Bolshevik regimes that propagated regional wars, fostered terrorism and destroyed economies. Not until 1989, with the fall of the Berlin Wall, was Lenin's malign influence definitively reversed. Its aftereffects will persist into the 3rd millennium. --John Keegan, historian