Cave Highline

Does anybody know if there has ever been a highline set in a cave?
i havn't found any information about it online.

just wondering what people think about it and if anybody has heard of anything like this before

Cool photos,
Is this PettiJohns cave

Being the first to do something is quite a drive. Is there any other reason to do this? Don't get me wrong, I love this aspect of being human and it helps move us forward, but why else do this?

Prove me wrong please.

I put this a little below sport rappelling (I actually kind of like exploring cliffs for new routes on rappel), but to each their own.

The coolest thing in those pics is the fist/ow looking crack above the slack line.