Raqqa, Syria (CNN) It was here, at the main square in Raqqa, that ISIS militants unveiled their brutality to the world -- they carried out public executions and placed the heads of the dead on spikes.

Those spikes still protrude from the square's perimeter fence, a chilling reminder of ISIS' barbaric reign over Raqqa that lasted nearly four years.

But little else in this Syrian city has survived.

The US-backed Syrian Democratic Forces (SDF) on Tuesday said that ISIS had been defeated in their heartland and Raqqa would be fully liberated in a matter of days.

ISIS declared Raqqa the capital of its envisaged caliphate, and for that reason it has been one of the most bombed-out places in the international fight against the group.

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