This is a view of the signature No. 8 hole at the Tom Fazio Course at Pronghorn. All that rock in the picture is volcanic, and the cave is the remnants of a lava tube. The No. 8 hole is a par-3 that plays 184 yards from the tips. It is described thusly on the Pronghorn Web site:
A 15-foot-deep pathway of rock leads you to a set of tees where the full glory of the 8th hole unfolds. Seven unique tees offer a variety of distance, angles and mountain views to choose from. Immediately, the cavernous tube creates an unforgiving natural barrier in front of the green, which must be played across a 50-foot drop. Carved out of a canyon of volcanic rock, the stunning green is surrounded by 25-foot walls jutting above an immense lava tube. Both sides of the trench dead-end into two giant caves that were created by molten lava.