ISIL once controlled territory in Syria and Iraq equivalent to the size of Great Britain, and imposed its version of Islamic rule on millions.
The group's fighters were defeated in Iraq two years ago, and it appears their dream of a so-called caliphate in Syria is over too.
US-backed fighters declared what they call the '100 percent territorial defeat' of ISIL after winning the battle for Barghouz.
Following weeks of intense fighting, Kurdish-led Syrian Democratic Forces raised their flag over the final Syrian town under ISIL control.
However, analysts are warning that ISIL's ideology remains strong.
So. has the group really been defeated?
Marwan Kabalan - Head of Policy Analysis, Arab Center for Research and Policy Studies
Judit Neurink - Journalist & author of 'The War of ISIS: On the Road to the Caliphate'
Mia Bloom - Professor, Georgia State University and author of 'Small Arms: Children and Terrorism'