[dehue]

Wow, I was not expecting to be taken to such an interesting website on my first click: http://www.goodearthgraphics.com/ This site has an underground cave directory by state, cave virtual tours with photos, cave type descriptions, cave photography tips and much more. I may just use this website to plan my next road trip and explore some caves.

[reaperducer]

And half of the entries have phone numbers ending in -CAVE.

Reminds me of the days when it was ordinary to memorize dozens and dozens of phone numbers, so one-offs had to be at least temporarily memorable.

[rhymeswithjazz]

There are three links at the bottom of that page that all still work. I'm a little surprised that link rot hasn't caught up to them.

[scriptkiddy]

Highly recommend Lake Shasta Caverns if you're ever in the area. Also, Mitchell Caverns in Mojave NP.