Massive stone bridges, among the largest in the world, cut by streams and rives. Arches, however, are formed by water erosion from the top. They both look the same to me. I took pictures of rocks nearby only 3 feet tall that seem to show the same erosion. With time, water, and support from harder rock on the side (like canyon walls would provide), arches (bridges?) would be formed.
[Please note: the featured image is a reflection from a pool under the bridge shot by an unknown NP staff member. Beautiful work. If anyone knows who to ascribe this to, please let us know so we can give credit to this wonderful photographer.]
This park also lies within the dark sky reserve, has an astronomy program and a new telescope. As we are travelling outside the season, no night sky program was available here. The old telescope was sent to Hovenweep National Monument, another dark sky site, but no one knows how to use it down there yet so we will just have to rely on binoculars, our “young” eyes, and our star guide app.