This one may also have been at Rocky Mountain National Park, or it may have
been somewhere else on that trip:
After going through Rocky Mountain National Park, my friend Mike and I spent
the night in Aspen (I need to dig up photos from there), and then drove on from
there to Black Canyon of the Gunnison:
A day or two later, after seeing lots of other neat stuff I should post
pictures of, we came out of the mountains and into the desert, and found this
and other neat rock formations along US Route 666,
the Highway of the Beast: