Krubera Cave is the deepest cave known on Earth and is over 2000 meters deep. That’s over 1.2 miles. That’s literally about as far as I can run.
If you’ve watched Planet Earth, you know that life can exist anywhere on Earth and indeed, arthropods live down under.
I want to toss a rock down there and try to listen for when it hits. Also, I like yelling in places that will echo my yelling and this looks like a great place for that.