US-backed forces captured the Islamic State in Iraq and Syria's (ISIS) last shred of territory in eastern Syria yesterday, ending the group's self-proclaimed caliphate after years of fighting.
Though the announcement marked a landmark victory, ISIS remains a potent threat. The militants switched gears as defeat loomed, seeding sleeper cells across former strongholds as they prepared a new insurgency.
SEE TOP OF THE NEWS: ISIS caliphate crushed