Title text:
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.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3266/
In the right conditions, an unprotected human in this cave will drown because the coolest spot for the water in the air to condense is inside of your lungs