You need to be fit, if you are not fit but you are bold enough afford the possibility of breaking a bone, go ahead, you don't have to be skinny but it helps, otherwise you have to be squeezable, no knee problems, no claustrophobics or people afraid of darkness or heights. I felt a little guilty to walk, well crawl in a place that has been under construction for the last 250 million years. I didn't even knew what spelunking is, but it was great. The tour takes a couple hours and there is no bathroom, water, or food available during the tour. You can't bring anything with you other than the equipment they provide. I don't know for how long this tour will be available, but if you feel like picking into the guts of mother earth, you should definitely go there. Rangers were great, is there a place to leave them a tip? it should be, because they did a great job. If you like a more nerdy experience, I recommend to read more about the formation of stalactites and stalagmites before you go, for this formations it can take up to 1000 years to grow 4 inches.
Here is a video of our visit
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