Grand Caverns, also called Weyer's Cave, is designated a Regional Park unlike the other caverns which are owned by private citizens.
Grand Caverns were rated by a magazine as number 2 caverns in the US. Our guide told us that Grand Caverns were special for three reasons: The size of the caverns, the vertical earth structure caused by an earthquake before the caverns were formed and more than 200 "sword structures." He said that the geologists did not really know how this sword structures were formed.
Grand Caverns is the oldest showcase caverns in the US. In 2006 it is going to be its 200 anniversary of public touring. On our tour we were able to see how the early people traveled using ladders, and at the Dante's Inferno how their candle was blown out. At one point on our right side we saw lots of names carved to the wall. The signatures belonged to the civil war soldiers. Stonewall Jackson did not enter the caverns and said "No, I think not. I fear I shall be underground soon enough, and I have no desire to speed the process!"
The kids would love the rainbow room, where they used different color for lighting. You can also get married in the Cathedral for only $100. Our tour guide told us that his grandmother, mother, and brother all get married in the Cathedral. They used to knock on the stalacmites to play them as an organ.
The entrance fee was $13.50 for adults. $1 off for triple AAA members, seniors and active military. There is a discount coupon for $1 in their website. We got a $1 off, thanks to our tour guide, when I question about what types of discounts they have.
We did not take our own advice and take a late tour. Our tour group was more than 30 which made the tour rushed. The tour half an hour later had only 8 people. Take the tour after 3:30 PM on a weekend at summertime. I definitely would like to revisit the Grand Caverns with a smaller group. The state park also has a swimming pool, picnic areas, and hiking trails.