Mount Olympus was a great mountain in the ancient nation-state of Greece, located in Europe's Mediterranean region on Earth. It figured heavily in the universe of Greek mythology as the home of the gods.
In reality, these gods were aliens with psychokinetic abilities that made them god-like to ancient Greeks. After Humans outgrew the need for such gods, they fled Olympus to Pollux IV. (TOS: "Who Mourns for Adonais?")
In planning Julian Bashir's surprise birthday party in 2371, the crew had the choices narrowed down to two different holosuite programs: a Greek palace on Mount Olympus or Louis Pasteur's house in Paris. (DS9: "Distant Voices")