Cameras prohibited. Hike a couple of miles into the Belizean wild. Three river crossings. Reach the entrance to the cave. Bats. Whip spiders. Darkness. Swimming, wading, crawling, climbing. Headlights and helmets. Archaeological ruins. Mayan pottery and ceramics untouched for more than a thousand years. Skulls. Bones. Human sacrifices. Natural formations and rivers.