Turkey is at the same time southeastern Europe and southwestern Asia (the Bosphorus is geographically part of Europe), bordering the Black Sea, the Aegean Sea and the Mediterranean Sea between Bulgaria, Georgia, Greece and Syria. Bosphorus is a channel that crosses Istanbul, which has been successively called Byzance by the Greeks, Constantinople by the Roman Empire and ottoman Sultans capital. Anatolia is made of high plateaus rising upto 1100 m.