Command & Conquer: Red Alert

In 1946, Albert Einstein finishes his time machine, dubbed the Chronosphere, and travels back in time to 1924, just after Adolf Hitler was released from prison in Landsberg. There, he creates a time paradox which erases the dictator from history, and returns to his starting point. With Nazi Germany removed from history, the Soviet Union is left unopposed as Joseph Stalin sees an opportunity to expand into Eastern Europe. In response, most of Europe ally against this new threat, and start a desperate war against the new aggressor.