World War II
World War II was an international conflict that was the decisive event creating the timeline of The New Order: Last Days of Europe, as the Axis victory propelled the Greater Germanic Reich and the Empire of Japan to the status of world powers and resulted in the destruction of the Allies.
In OTL, the Germans do not conquer the British mainland as Operation Sealion fails, and the Germans fail to capitulate the Soviet Union in Operation Barbarossa. In the timeline of TNO, though, the Germans succeed in many of the decisive operations that failed for the Germans in OTL.