Ken X.
Google
This is the most spectacular arch in the park for me and a must visit point.
The trail that leads to it is quite strenuous, takes about an hour. The view during the hike is also awesome, you can look around the views when taking a break. The trail is on top of enormous rocks, so there is no where to hide from sun, take water and apply sun protection.
The arch is speechless, just see the pictures I took.
If you have time, you can watch the sunset here.