For centuries, Aleppo was the largest city in the Syrian region, and the Ottoman Empire's third-largest after Constantinople (now Istanbul) and Cairo. The city's significance in history has been its location at one end of the Silk Road, which passed through Central Asia and Mesopotamia. When the Suez Canal was inaugurated in 1869, much trade was diverted to sea and Aleppo began its slow decline. At the fall of the Ottoman Empire after World War I, Aleppo lost its northern hinterland to modern Turkey, as well as the important Baghdad Railway connecting it to Mosul. In the 1940s it lost its main access to the sea, Antakya and İskenderun, also to Turkey. The growth in importance of Damascus in the past few decades further exacerbated the situation. This decline may have helped to preserve the old city of Aleppo, its medieval architecture and traditional heritage. It won the title of the "Islamic Capital of Culture 2006", and has had a wave of successful restorations of its historic landmarks. The Battle of Aleppo (2012–2016) occurred in the city during the Syrian Civil War, and many parts of the city suffered massive destruction. Affected parts of the city are currently undergoing reconstruction. An estimated 31,000 people were killed in Aleppo during the conflict.