|We had a very nice stay in City of Rocks State Park. We didn't go anywhere outside the park, and that is a first for us on this trip. (The park itself is in the middle of nowhere in western NM.) The "rock city" was formed when rock was pushed out during a volcanic event. When it cooled it formed vertical fissures. Over time, wind and sand eroded the fissures leaving large rock formation standing like buildings. Eventually, these rocks will be reduced to the sand that surrounds the area and the interesting outcroppings will disappear. There is no urban light pollution in this area so the night sky was magnificent. We were there on moonless nights and the milky way and billions of stars could be seen. The state park has an observatory that is run by volunteers, it is open one night a month. Sadly, we missed it by one night. This is a must see place for anyone interested in earth sciences.