The helmet headlight was essential to see where we walked on craggy rocks and ice.

When we all gathered here at the end of the lava tube, our guide told us to turn off our headlights to see how dark it was. Yes, it was pitch black. Our ears then concentrated on the water drops falling from the ceiling. Great place to meditate. The temperature was near freezing, but we had enough clothing. I wanted to ask the guide what would happen if there were a big earthquake while we were inside. But I refrained from doing so because I didn't want to alarm the others...