Some 3,500 terrorists were holed up in the caves before their defeat in August. They turned their underground shelter, which covered 10,000 square meters, into a stronghold from which they could operate autonomously.
Numerous crates with ammunition and weapons, including what appears to be American TOW anti-tank missiles, still remain abandoned in the tunnels.
Besides the command center and cages for prisoners, the caves also hosted a drone factory that produced UAVs for surveillance missions and the delivery of bombs. Some of the drones made there were so advanced that they could reach a height of 4,000 meters and cover distances of up to 150km.
Also among the discoveries was an underground hospital. The Syrian Army said that the medical facility was not only used to treat wounded fighters, but served as a movie set as well.
Damascus says the makeshift studio is where the infamous Western-backed aid group, the White Helmets, filmed the video of a fake chemical attack in Khan Sheikhoun in 2017.
Back then, blame for the incident, which has never been definitively settled, was pinned on Damascus, and the White Helmet videos became a pretext for a missile strike on Syria by the US and its allies. Now the uniforms of the White Helmets can be seen scattered among the rubble in the caves.
Though the terrorists have vacated the tunnels, the underground stronghold remains a dangerous place. Sappers are now working in the cave to determine what explosive devices may have been left behind by the retreating militants.