Boulder, Colorado

Geologists estimate the age of these rock formations along the east and south slopes of Green Mountain as 290-296 million years; they were lifted and tilted into their present orientation between 35 and 80 million years ago. Or perhaps, you were around more recently in the 40’s and 50’s, when overeager students climbed them and wrote “CU” in huge white letters upon its slope. Either way, you must admire the omnipresent majesty of the Flatirons, a ubiquitous symbol of Boulder.