We went on a Mayan ruin tour followed by a cave swim in the 7 mile cave. This was a ton of fun. Dave managed to lose his head lamp when he dove into the water. We spent 15 minutes searching the water for it. Fortunately Dave managed to retrieve it 8 foot under water and we were off. After swimming back 1/2 mile or so, we turned off all the lights. It was so black everyone felt disoriented as if you didn't know which way was up or down. The bats were not so amused though. They felt that the intrusion deserved much objection.