Jewel Cave National Monument is just east of Custer State Park. The cave is different than the other two I'd visited recently (Carlsbad and in Great Basin). It had calcite spars that grew from the walls, looking just like jewels (pic: http://www.nps.gov/mwr/customcf/apps/CMS_HandF/GreenBoxPics/JECA_spar%20photo.jpg).
http://www.nps.gov/jeca/images/Hydromagnesite-Balloon.jpg). Unfortunately, the tour that I went on didn't have any of these balloons ... but they are so cool all the same!
At 135 miles, Jewel Cave is the second longest cave in the world. The first longest is Mammoth in Kentucky that I plan to visit in a few months.
I camped two nights at Center Lake at Custer State Park. As in the "White Hills," it rained alot in the "Black Hills" too. I got a great thunder and lightening show one night. I could hear the thunder after it passed for miles away as it echoed in the valley I was in.
Kudos to the State of South Dakota for making Custer State Park a great place to vacation. One of my favorite things to do here was to take their wonderful scenic drives. The Iron Mountain Road has 3 tunnels that perfectly frame Mount Rushmore National Memorial as you drive through them. It also as a couple of pig-tail turns where you go under a bridge that you just crossed over (pic: http://gfp.sd.gov/state-parks/directory/custer/images/pigtail-bridge.jpg). Amazing and fun!
The Needles Highway is also in this park and is probably my all-time favorite drive so far. It has spires of granite that line the road as they reach for the sky ... feels almost like church. One place is even called "The Cathedral." Sylvan Lake is off of this highway where granite spires come right out of the water ... another amazing place. There's also several very cool one-lane tunnels blasted through the granite to make this road. Close to one of those tunnels is a rock formation that looks just like a hole in a needle that you would thread. Pretty amazing. (pic: http://www.custerresorts.com/images/apg_1206024000.jpg)
Wildlife Loop Road is the drive I took most often to see buffalo, elk, pronghorn, burros, prairie dogs, blue birds, deer, mountain goats, big horn sheep ... you just never knew what was going to be there. I also took the back roads that are inside of the loop for some more great scenery and wildlife. The park does a good job at keeping all of their gravel roads well groomed. Pronghorn were everywhere (pic: http://gfp.sd.gov/state-parks/directory/custer/images/wildlife/pronghorn.jpg).
originally posted 6/18/10