Pillars of Hercules
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. The two rocks that are most likely to be Abial Mons are Monte Hacho in Ceuta and Jebel Musa in Morocco.