Khangkhui Cave is a natural limestone cave in Ukhrul district. The Krubera Cave is the deepest known cave in the world. It was the first white pigment used by prehistoric artists in cave paintings. Other styles include cave, forest and mountain temples. There are two burial tombs, a painted Hellenistic cave and a Roman cave. They take the shape of a shallow cup stuck to the cave wall. Bat guano is integral to the existence of endangered cave fauna. The three figures stand near a dark empty cave. It would cave in and bring down the structure above. There are also bats roaming the cave. Misleading signs were placed along the roads leading to the Mammoth Cave. The family spend time sheltered in their cave. The story of human beings in relation to Mammoth Cave spans five thousand years. There was only one fragment found in Cave 9. A specimen from Powder Mill Creek Cave, Missouri, was dated at 13,170YBP.