Our probably last national park visit is Arches, just outside of Moab, UT. Unfortunately it was a bummer of a day to visit: we watched the sun rise on The Windows and then never saw it again.
My own geology lesson for the day was the difference between a natural arch and a natural bridge. A bridge is formed by a running water, so the rock spans the water and the water eats away at the bases of the sides, while an arch is more traditional erosion of frost, wind, and occasional water separating softer, less stable materials, from harder materials. In Arches' case, this is salt and sandstone.
Rain finally drove us out of the park and town so we headed east along a scenic route to Colorado Springs. At Frisco we turned south toward Breckenridge. With a different tour bus, I would have gone over the unpaved Boreas Pass to Como, the route of an old narrow gauge railroad, but instead we took Hoosier Pass to Alma, the highest incorporated town in the country at 10,578. [Leadville is the highest incorporated city. Details details.]
Turning north at Fairplay, passing Como and the Boreas Pass road, we headed to Jefferson, and a right turn onto Tarryall Road (Hwy 77). Tarryall Reservoir is like the Garden of Eden hidden among the high desert. Eventually we joined the more traditional highway into Colorado Springs and bombed down past Pikes Peak. What a final exclamation point on our time in the mountains.