This in an immense cave system of cathedral chambers which will take us close to two hours to see.  Apart from the impressive natural structures, this cave system is historically and culturally important.  In it have been found the bones of a mammoth, ceramics dating back to 2000 B.C., many chultunes full of "virgin water" used in religious ceremonies, giant columns that hum out "lol-tun" when tapped, natural formations with startling resemblances to persons and animals, carvings and hieroglyphic inscriptions. Toward the end of our tour, we will come to a cavern with a partially collapsed roof, allowing the entrance of sunlight.