Well, Southwest Asia actually has a natural division: the Dardanelles link the Aegean Sea to the Sea of Marmara, which then is linked to the Black Sea by the Bosporus Straits. The problem lies in the fact that countries lie on both sides and in grey spots. While the Ural Mountains are the technical geographical divide between Europe and Siberian Asia, Russia controls both sides, so is Russia in Europe or Asia? And if Russia is in Europe, then do you continue Europe to include nations that lie in the Caucasus, which lie directly east of the Black Sea but west of the Urals? Turkey owns land on both the European side of the Sea of Marmara and on the Asian side. Cyprus lies on an island in the Mediterranean Sea, and while its closer to Asia, it is in the EU. Even Greece becomes a grey area, because it owns islands that are barrier islands of Asia Minor, and Kazakhstan is grey because the Urals end in the middle of the nation.
