On my trip to the South Dakota I made a side trip into Wyoming to see the Devils Tower. It was about a 1 hour drive west of Deadwood, SD. You head down the interstate to Sundance, WY (home of the Sundance Kid) and then turn north up a fairly scenic highway that leads to the Devils Tower.
Once you see the Tower you are completely hooked. It is a magnificent structure!
It cost $12/vehicle to enter the park area, which was worth it. You can drive right up to a parking area where several different trail-heads are found. Looking up at the tower is wonderful, and when I was there several eagles soared up and down the sides of the tower.
I also drove down a road behind the tower and took a few spectacular photos.
On the way back to South Dakota, I took an alternate route that took me past the small town of Aladdin, Wyoming. Check out the photo below.
All and all, the side trip to Devils Tower was great!