A 145 foot waterfall flowing 1100 feet under the heights of Lookout Mountain, the long elevator ride down and quarter mile walk throught the depths of Lookout Mountain to Ruby Falls is well worth the time and effort. Look forward to beautiful calcite formations and tour guides joking about leaving you down there forever. After about the eighth "leave you behind" quip, you begin to wonder if they are serious.
Up on the moutaintop, there is a sluice where for a few dollars you can have your kids pan through a box of local dirt for interesting rocks and minerals of the area. The nearby gift shop also has many interesting pieces of polished rock available for souvenirs besides a hundred different wildlife and mountain T-shirts. Also find a convenient playground area for the youngsters.
There is also an incline railroad ride to consider as well as Lover's Leap lookout where seven states can be observed. For more info access link