We visited famous Mammoth Cave National Park in Kentucky and took some of the many tours underground in the caverns and tunnels. This tour the National Park Ranger took us down one of the traditional pathways into a large cavern with a single lantern and then turned it off to show us what total darkness was like. Apparently in the late 1800’s a preacher used to take a large congregation down into the caverns using oil lamps to light the way. When they got to a famous cavern, they would gather and the preacher would go up on a ramp to a high location and take all the lanterns with him.
Behind this spot you can still see the soot up on the wall from the many lanterns. His lectures would last 1-2- and even 3 hours and amazingly, no one left. That is because the preacher had all the lanterns and there were no other lights to find your way out in the total darkness.