Mosul is a major city in northern Iraq, serving as the capital of Nineveh Governorate. Approximately 400 km north of Baghdad, Mosul lies on the Tigris river. The Mosul metropolitan area has grown from the old city on the western side to encompass substantial areas on both the "Left Bank" and the "Right Bank", as locals call the two riverbanks. Mosul encloses the ruins of the ancient Assyrian city of Nineveh on its east side.
At the start of the 21st century, Mosul and its surroundings had an ethnically and religiously diverse population; the majority of its population were Arabs, with Assyrians, Armenians, Turkmens, Kurds, Yazidis, Shabakis, Mandaeans, Kawliya, and Circassians, in addition to other, smaller ethnic minorities. Mainstream Sunni Islam was the largest religion, but there were a significant number of followers of the Salafi movement and Christianity, as well as Shia Islam, Sufism, Yazidism, Shabakism, Yarsanism and Mandaeism.
Mosul's population grew rapidly around the turn of the millennium and by 2004, it was estimated at 1,846,500. In 2014, the Islamic State of Iraq and the Levant seized control of the city.