The Bosporus or Bosphorus, also known as the Istanbul Strait, (Turkish: İstanbul Boğazı) (Greek: Βόσπορος) is a strait that forms the bounary between the European part (Rumelia) of Turkey and its Asian part (Anatolia). The world's narrowest strait used for international navigation, it connects the Black Sea with the Sea of Marmara (which is connected by the Dardanelles to the Aegean Sea, and thereby to the Mediterranean Sea). It is approximately 30 km long, with a maximum width of 3,700 metres at the northern entrance, and a minimum width of 700 metres between Kandilli and Aşiyan; and 750 metres between Anadoluhisarı and Rumelihisarı. The depth varies from 36 to 124 metres in midstream. The shores of the strait are heavily populated as the city of Istanbul (with a metropolitan area in excess of 11 million inhabitants) straddles it.