In the 19th century, Kentucky's Mammoth Cave launched an entire, very competitive cave tourism industry in the area, In 1925, Floyd Collins was trapped in the cave system, which was the beginning of the end of the cave wars.
Research:

SYMHC Classics: COINTELPRO 1
39:12

Behind the Scenes Minis: It's Not Unprecedented
16:46

The Rendition of Anthony Burns, Part 2
43:32