In 1913 Hitler,Trotsky and Stalin were in Vienna. They visited the same cafe. What if Lenin and Mussolini also went there while got blown up a revolutionary ? I guess the October revolution fails. So Russia remains in WW1 preventing the Spring Offensive. No CCP either. While communism remains a fringe ideology. Hitler isn't there to bring Nazi Party to power. So no WWII. Mussolini isn't there to bring Fascism to power. So it remains a fringe ideology.