Hayat Tahrir al-Sham, whose name means Organization for the Liberation of the Levant, was the main rebel group leading the latest offensive, launching a surprise assault in late November from northwestern Syria that quickly led to the fall of President Bashar al-Assad. It is now leading the transition to a new Syrian government.

CNN mapped how rebel groups captured several key cities, cutting off pro-regime forces and successfully toppling Assad’s regime after 11 days of fighting.

The fall of the Assad government in Syria took almost everybody by surprise and has created uncertainty for competing foreign interests that had established lines of control most assumed were frozen in the region.