[dvh]

Hover text is "If you're thinking 'Wait, a giant crystal cave in Mexico? What's that?' then I'm SO excited for the image search you're about to do."

[basilikum]

https://en.wikipedia.org/wiki/Cave_of_the_Crystals

[rus20376]

Forget about that, I just learned there’s a salt mine under Detroit!

[throw-the-towel]

There's also one under Yerevan, Arnenia. Funnily, the altitude differences in the city are so large that the bottom of the mine is still higher above sea level than the city center.

[pchristensen]

I'm excited for them too!

[sph]

Haha I definitely googled that, and I was not disappointed