In the background in this picture, you can see the Garden Wall. It is a famous example of an arête. The word “arête” is french for edge, and refers to a narrow ridge of rock which separates two valleys. It is usually formed by two glaciers eroding parallel valleys (thanks, Wikipedia).
I’m amazed when I see a canyon formed by a swiftly moving river (think Grand Canyon), but my mind is somehow able to see the water carving through rock over many, many years. My mind struggles to imagine the time it takes for ice flowing a few feet per day to carve out canyons like those in Glacier NP. How then can we grasp the idea of eternity?