Turkey is located at the crossroads of Europe and Asia, and is bordered by eight countries. The Mediterranean Sea is to the south; the Aegean Sea is to the west; and the Black Sea is to the north. The Sea of Marmara, the Bosphorus and the Dardanelles (which together form the Turkish Straits) demarcate the boundary between Thrace and Anatolia; they also separate Europe and Asia.
Hagia Sophia (from the Greek: "Holy Wisdom") is a former Greek Orthodox patriarchal basilica, later an imperial mosque, and now a museum in Istanbul, Turkey. From the date of its construction in 537 until 1453, it served as an Eastern Orthodox cathedral and seat of the Patriarchate of Constantinople, except between 1204 and 1261, when it was converted to a Roman Catholic cathedral under the Latin Empire. The building was a mosque from 29 May 1453 until 1931. It was then secularized and opened as a museum on 1 February 1935.