This is the "pinnacle": a 28 meters high needle of rock that was left standing as the other rock was cut away to make entry from the north side near impossible. It supported a drawbridge that led to a secondary entrance to the castle.
My guidebook indicates the ditch was probably deepened, but not originally dug, by the Crusaders, it claims the Byzantines, who kept the fort before, had done most of the work.
We'll continue on our way to the main entrance.