Oceanus ( ; Greek: Ὠκεανός "Ōkeanós", ] ), also known as Ogenus ("Ogenos", Ωγηνος) or Ogen (Ωγην), was a divine figure in classical antiquity, believed by the ancient Greeks and Romans to be the divine personification of the sea, an enormous river encircling the world.
Greeks and Romans thought water would fall off the earth.