Lots of plausible alternative histories don't end with the destruction of Nazi Germany. Others already named some, another is if the RAF collapsed during the Battle of Britain and Germany had established air superiority. The Germans would have taken out the Royal Navy and mounted an invasion of Britain soon after; if Britain had fallen there'd have been nowhere for the US to stage D-Day. Hitler could have then diverted all resources to the eastern front and possibly managed to reach Moscow before the winter set in.