A look at Aleppo, Syria’s key northern city:
Syria’s largest city and once its commercial center, Aleppo was a crossroads of civilization for millenniums. It has been occupied by the Greeks, Byzantines and multiple Islamic dynasties. As one of the world’s oldest continuously inhabited cities, Aleppo’s Old City was added in 1986 to UNESCO’s list of World Heritage sites.
But the civil war has damaged its landmarks, including the 11th-century Umayyad Mosque, which had a minaret collapse during fighting in 2012; the 13th-century citadel; and the medieval marketplace, where fire damaged 500 shops in vaulted passageways.
Aleppo was one of the last cities in Syria to join the uprising against President Bashar Assad’s government.
A number of insurgent groups control several neighborhoods. The only rebel supply line is a corridor that links the city with northern parts of the province leading to Turkey.
Government forces and their allies control most of the eastern neighborhoods, plus the international airport and the Nairab air base.
Militants from the Islamic State group used to control several neighborhoods in Aleppo, but they were forced out by other rebels in early 2014.
The main Kurdish militia, known as the People’s Protection Units (YPG), controls several predominantly Kurdish northern neighborhoods.
The main insurgent groups in the city are the ultraconservative Ahrar al-Sham group; the Nour el-Din Zengi; the Tawhid Brigade; and the Nusra Front, al-Qaida’s branch in Syria. Smaller groups also are involved in the fighting.