Former Home of the Greek Gods
Mount Olympus is the highest mountain in Greece and the original location of Olympus, the original home of the Greek gods. It is no longer the location of Olympus because as Chiron explains, the city of Olympus has steadily moved west following the center of power of the "Western Civilization" over the centuries and is now in the United States of America. Olympus is currently located far above the Empire State Building on the 600th floor, while the original mountain remains in Greece.
While Olympus moves with Western Civilization, the "roots" of the Olympians are still there. It is also revealed that that's where the Giants plan to go as it's the only way to actually defeat the gods.
- The tallest mountain on the planet Mars is called Olympus Mons (Latin for Mount Olympus). It is also the tallest mountain on any planet in the Solar System.