Germany was split into four zones of occupation: One French, one British, one American and one Soviet. Eventually the Western Allies consolidated their holdings into the Federal Republic of Germany, aka West Germany. The Soviets set up a communist state (the German Democratic Republic, in East Germany. Until the end of the cold war, Germany was split in half and each half was on a different side of the conflict. Germany was projected to become a major battleground should a ground war in Europe break out. So regardless of the other border changes that took place after ww2, the split of Germany was likely the most significant. Or it could be Korea because of communism