Pillars of Hercules

promontories that flank the entrance to the Strait of Gibraltar

The Pillars of Hercules are the mountains on both sides of the Strait of Gibraltar. People in ancient times named them. Modern historians know that the northern Pillar, Calpe Mons, is the Rock of Gibraltar. But modern historians do not know which rock on the south side is the other Pillar, Abila Mons. Historians have argued about this for hundreds of years.[1] The two rocks that are most likely to be Abial Mons are Monte Hacho in Ceuta and Jebel Musa in Morocco.

The European Pillar of Hercules: the Rock of Gibraltar (foreground), with the North African shore and Jebel Musa in the background.
Jebel Musa, one of the candidates for the North African Pillar of Hercules, as seen from Tarifa, at the other shore of the Strait of Gibraltar.
Jebel Musa and the Rock of Gibraltar seen from the Mediterranean Sea


  1. Strabo summarizes the dispute in Geographia 3.5.5.