Carlsbad Caverns, NM.
Just got back from Carlsbad. We took our niece and nephew-in-law and our great nephew who is almost 7.
There are many caves at Carlsbad Caverns, Since we had a 7 year old with us, we only did the Natural Entrance and the Big room self guided tours. The rest require a guide and some climbing and crawling.
About ten minutes in to the cave, I realized I had left my e-cig in the car.
But with 4+ hours of spelunking ahead of us, I didn't miss it.
It was raining when we got there, and at first they had the natural entrance closed due to lightning. The lightning subsided long enough for us to make it in. We had to do the 5 minute hike to the entrance in the rain and got soaked. The temperature in the cave and at 750 feet under ground, is a constant 56 degrees Fahrenheit year around, so at first we were all a bit chilled from being wet, until we got warmed up from hiking and eventually dried out.

This is the Natural entrance.

The Towers

This is the Famous Rock of ages.

Sharks mouth

Just a typical view from within the Big room. The Big room is over 14 football fields in size.
There are some more pictures of the cave here.
http://www.e-smokers-forum.com/membe...-carlsbad.html