[SL61]

At Mammoth Cave in Kentucky they turn off the lights on every tour. On one tour, my guide turned off the lights and seemed to lose track of time. He started talking about different things, meandering into other topics, without turning the lights back on. It lasted 9 minutes, according to my watch.

The first couple minutes were nothing special, and I was still fully aware of the group of people around me. After a few minutes I noticed a faint light. I don't know if it was a distant tour light around the corner, or if I was hallucinating. I spent a couple minutes looking and trying to figure it out. Around that point I became really uncomfortable, and my heart rate increased as it went on.

My natural reaction would be to close my eyes - if they're closed then surely I'll be immune from the effects of darkness. But this actually increased my anxiety. When it's pitch black there's no visible difference between having your eyes open or closed. It feels like your eyelids aren't working, like the muscle movements are not happening.

It caused a retreat into my own mind. Despite there being twenty people nearby, I felt like they weren't real. It didn't help that the group was quiet, with only occasional shuffles and murmurs coming from them. I started to think they could all walk off, leaving only me and the rambling tour guide. I had a strong urge to light up my watch or phone, but I didn't want to be "that guy". My eyes felt like they ceased to exist.

By the last couple minutes I stopped pondering and noticing things, and started waiting for the guide to turn the lights back on. I think the rest of the group was going through the same thing, judging by their silence. I was surprised at how quickly things returned to normal after they came back on. I had felt like I was near a breaking point of some sort, but within seconds I was fine.