Turkey, known officially as the Republic of Turkey, is a Eurasian country that stretches across the Anatolian peninsula in southwest Asia and the Balkan region of southeastern Europe. Turkey borders eight countries: Bulgaria to the northwest, Greece to the west, Georgia to the northeast, Armenia, Azerbaijan (the Nakhichevan exclave), and Iran to the east, Iraq and Syria to the southeast. It borders the Mediterranean Sea to the south, the Aegean Sea to the west, and the Black Sea to the north. Turkey also contains the Sea of Marmara, which is used by geographers to mark the border between Europe and Asia, thus making Turkey transcontinental.