Most arches take a long time to form. This one formed instantly in 1940 when the middle fell out. I have pictures of the pieces on the ground below.
Note the cars at the base in the foreground.
Arches NP is a lot more then arches but they are the formation that seems to be the most unique. There are lots of other formations here that would make the place special even without the arches. There is not a lot I can add to the pictures so I will just let them speak for themselves. I will only say that without the scale that having a person in the picture provides it is very hard to tell from a photograph how big some of these formations actually are.
Our plan is to go to Canyon Lands tomorrow and then come back here the next day to hike up close to some of the arches we missed today.