sentences:  To access the interior of the cave when tours were no longer being offered, visitors had to walk about one-quarter mile down a waist-deep stream that ran through the cave.There had been a cave-in at the rear of the cave that blocked off what were rumored to be miles of additional passages.At least three endemic species were exterminated when the cave was inundated in 1967 – the crustacean "Caecidotea nickajackensis", the pseudoscorpion "Microcreagris nickajackensis" and the ground beetle "Pseudanophthalmus nickajackensis".