" This is the only place in the whole Rocky Mountain front where you can go from the Great Plains to the summit of the mountains without snaking your way up a mountain face or going through a tunnel. This one feature had more to do with the building of the West than any other factor. I don’t diminish the importance of the Oregon Trail, but here you had everything going for you. This point hasn’t been made before. "

― John McPhee , Rising from the Plains