Kartchner Caverns State Park
Discovered in 1974, the caverns are 2.4 miles long and is considered a wet and live cave, meaning that the calcium carbonate continues to deposit and grow.
You will have to call the Visitor Center first if you are really intent to going into the caverns --- also the big chamber is not open all the time, so you have to check with them.
Yes, there are guided tours available—however, these are so difficult to get at times – only one hundred people allowed in a day or something like that, and some of the tours can only be bought on a first-come first-served basis.
Tour hours vary by season and Reservations are highly recommended for busy times of the year, weekends and holidays. Reserve online through website (registration required) or by phone at 520-586-2283
The Visitor Center also has interactive displays, a theatre with video programs and a gift shop. The park also has about 62 campsites, five miles of hiking trails and even a hummingbird garden.
2980 Route South 90
We visited Kartchner Caverns State Park in 2005. It lies 49 miles east of Tucson. Although there are hiking trails in Kartchner Caverns State Park, the main reason people visit this park is for the cave. Randy Tufts and Gary Tenen discovered Kartchner Caverns in 1974, and they kept their discovery a secret for another 14 years. Now established as an Arizona State Park and open to the public, the cave has been a popular destination for those who love caves. For this reason reservations are strongly recommended. Two tours are currently offered and are guided by trained tour guides. Of the two, my favorite was the Big Room which is only open October 15 - April 15. This is because the Big Room is a bat nursery doing the other months of the year. The cave averages a temperature of 70 degrees with a 90% humidity, so this is a warm cave. You will be too warm if you bundle up with warm clothing. Since this is a living cave, with the formations still growing surfaces are wet. Because of the wet surfaces and steep grades within the cave strollers, walkers, and backpacks are not allowed on the tours. Small children who cannot walk must be carried in your arms. Please note that as of 2005 no photography is allowed within the caverns. They are, however, considering developing a photography tour in the future. If you wish to make this a destination, the state park also contains a campground.