Nem, thank you so much for sharing that, I had no idea just how exciting is the ground under where I live.
One of the most enjoyable 8 minutes I have spent in many a long day.
There is excellent photography throughout, and haunting music, making it very watchable indeed.
(Not to mention the blonde female caver, who is rather easy on the eye.)
Features of interest are the 'unknown' minerals, and calcium falls.
I had no idea that so many different minerals were in abundance beneath my feet.