The 13-year civil war in Syria has roared back into prominence with a surprise rebel offensive on one of Syria’s largest cities and ancient business hub.

Eight years ago, Syria’s civil war shifted in President Bashar Al-Assad’s favor after a Russian blitzkrieg on Aleppo helped him regain control over the country’s second biggest city.

The retaking of Aleppo marks the first major development in years in Syria's grinding civil war, which had largely fallen from the world's headlines. It also raises fresh questions about the opposing sides,