A lightning offensive in Syria last week broke a prolonged stalemate 13 years into Syria's civil war and emphasized the vulnerability of Syrian President Bashar al-Assad's regime. Why it matters: Rebels last week reclaimed nearly all of Aleppo,

Iran and Russia, both stretched by conflicts of their own, have experienced setbacks in Syria after a rebel offensive in the northwest of the country.

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.