Someone asked this on the current WW2 thread.

Germany would have emerged as the century's first true "superpower," with control of all of Central and Eastern Europe. The Brest-Litovsk treaty with the new Soviet Union, which was nullified by the German defeat, gave Germany direct or indirect control of most of European Russia (including Poland, Belarus, Ukraine, Finland and the Baltic states). A third of the Tsarist empire's population, half its heavy industry, and nine-tenths of its coal mines were ceded to German control in one of history's most humiliating peace treaties. It was far more punitive - and unalterable - than the Treaty of Versailles that the Allies forced on Germany.

It's impossible to predict what the future of the Soviet Union would have been had Germany been victorious in WW1. There could have been a successful counter-revolution against the Bolsheviks who accepted the Peace Treaty

Had Germany and the other Central Powers come out as victors, Belgium and the Netherlands would have become virtually vassal states of the German Empire. A strengthened German Navy would have permanent bases onj the Dutch and Belgian coasts. The Belgian Congo (and undoubtedly the French Congo as well) would have become German along with most (even all) of the French and British African Colonies. Eventually French Indochina would probably have come under German control. Various additonal concessions (if possible) would have been exacted from Britain and France and had the war gone on past 1916, the United States and Japan (which also had sided with the Allies). Austria would have taken some Italian territory and incorporated all of Serbia into its own Empire. The Turks would have retained control of the Middle East and the Arab world.

The world would have looked so different from what we're used to that almost anything could have happened, including successful Marxist uprisings in Central and Eastern Europe regardless of events in Russia. A vengeful Fascism could well have taken root in Britain and France, taking its cue from a bellicose Mussolini in Italy. Or Britain and France might have turned Communist and allied themselves with Russia against the Central Powers. In that case, Germany would have become the most nearly democratic power in Europe.

Without Hitler there would have been little motivation for a European Holocaust. A second World War (with a neutral United States), and the development of an atom bomb, probably by Germany or Britain, might have been delayed though probably not averted.