I have always wanted to visit the Mammoth center in Hot Springs,SD since even before I saw the documentary movie "Ice Age, the melt down". I finally made it today and it was well worth the time spent. If you do a google search you can read all about what is going on here, but in short it is an ongoing archaelogical dig under contolled conditions inside of a building. I think they said that the first bones were discovered in 1975. Do the search, it will be worth your time.