(COLORADO SPRINGS) — Rocky Mountain National Park (RMNP) is celebrating the end of Earth Science Week by revisiting the geologic history of the Rocky Mountains.

RMNP says that throughout geologic history, there have been three distinct mountain ranges in what is now known as the Rocky Mountain National Park.

Roughly 70 million years ago, the Laramide Orogeny, a series of mountain-building events uplifted the modern Rocky Mountains, according to RMNP. The event was soon followed by extensive volcanic activity, which left behind rocks in the Never Summer Range of the Rocky Mountains.

The Never Summer Range is what remains from the volcanic activity that occurred 30 million years ago. A second period of uplifting further raised the Rockies nearly a vertical mile to their present height, states RMNP.

To learn more about the geological history of the Rockies, visit the link above.