Mount Olympus is formed of sedimentary rock laid down 200 million years ago in a shallow sea. Various geological events that followed caused the emergence of the whole region and the sea. Around one million years ago glaciers covered Olympus and created its plateaus and depressions. With the temperature rise that followed, the ice melted and the streams that were created swept away large quantities of crushed rock in the lowest places, forming the alluvial fans, that spread out all over the region from the foothills of the mountain to the sea. The Geological Museum of Mount Olympus, located in Leptokarya, provides detailed information about the geological structure of the mountain.