Rebel troops in Syria have made significant gains over the last week. For the first time in eight years, rebels have taken control of the northern city of Aleppo, which is situated near the Turkey-Syria border.

Observers saw insurgents stomping on posters, some depicting Syrian president Bashar al-Assad, and  burning Syrian flags.

The insurgents belong to the organization Hayat Tahrir al-Sham (HTS). The United States once designated the group as a terrorist organization after its alliance with Al-Qaeda, the terrorist organization responsible for the Sept. 11 attacks on the World Trade Center and the Pentagon. Since then, the group has separated from Al-Qaeda.

Despite the novelty of the attack, the war in Syria is hardly a new event. Conflict erupted nearly 13 years ago due to a government crackdown on protesters during the Arab Spring uprisings, which swept through the Middle East in the early 2010s.