About 520 B.C. a certain Hanno made a voyage that is still one of the most notable in the world. This Hanno - if we may trust the Periplus of Hanno, the Greek translation of his account which still survives - followed the African coast southward from the Straits of Gibraltar as far as the confines of Liberia. He had sixty big ships and his main task was to found or reinforce certain Carthaginian stations upon the Morocco coast. Then he pushed southward. He founded a settlement in the Rio de Oro (on Kerne or Herne Island), and sailed on past the Senegal River. The voyagers passed on for seven days beyond the Gambia, and landed at last upon some island. This they left in a panic, because, although the day was silent with the silence of the tropical forests, night they heard the sound of flutes, drums, and gongs, and the sky was red with the blaze of the bush fires. The coast country for the rest of the voyage was one blaze of fire, from the burning of the bush. Streams of fire ran down the hills into the sea, and at length a blaze arose so loftily that it touched the skies. Three days further brought them to an island containing a lake (?Sherbro Island). In this lake was another island (?Macaulay Island), and on this were wild, hairy men and women, "whom the interpreters called gorilla."
The Carthaginians, having caught some of the females of these "gorillas" - they were probably chimpanzees - turned back and eventually deposited the skins of their captives - who had proved impossibly violent guests to entertain on board ship - in the Temple of Juno.
Hanno's own account mentions a notable landmark.
"Sailing quickly away thence, we passed a country burning with fires and perfumes; and streams of fire supplied from it fell into the sea. The country was impassable on account of the heat. We sailed quickly thence, being much terrified; and passing on for four days, we discovered a country full of fire. In the middle was a lofty fire, larger than the rest, which seemed to touch the stars. When day came, we discovered it to be a large hill, called the Chariot of the Gods."
So that's what the map is referring to. But even if you leave space aliens out of it this kind of extraordinary voyage would make a great basis for a game. It could either be an epic campaign, with players undertaking the whole voyage from beginning to end, or it could be a jumping off point for more episodic adventures. Fabulous ruins, mysterious civilizations, lost Atlantean colonies -- any number of adventures await. It would be like a cross between Conan, Tarzan and the old Wagon Train TV series, only set in ancient Africa.