about 1/3 of the way in from the lower entrance. Here 14 skeletal remains have been found, and numerous examples of ancient Maya pottery remain. The cave periodically closes when rainfall causes the river's water level to rise and potentially flood parts of the cave. Conservation In late May 2012, a tourist accidentally dropped a camera and fractured a human skull estimated to be over one thousand years old. As a result, all cameras without a permit are banned from the cave. A different visitor once broke another skull by accidentally stepping on it. All visitors are told to remove their shoes and wear socks when reaching the upper dry chamber to help minimize foot traffic impact. Media Ghost Hunters International season 3 episode 9 "The Crystal Maiden: Belize and France" evaluated the ghost stories behind the mysterious maiden. National Geographic listed it as #1 on their list of Top 10 Sacred Caves. The cave and its tourism are a main subject of the speculative science fiction novel The Actual Star. See also Maya cave sites References Further reading Marachov, Nick and Williams, Nick (ed) Below Belize ca. 1991. Miller, Tom Tunichil Muknal The Canadian Caver vol 21 no 2, 1989. Williams, Nick An Introduction to Cave Exploration in Belize. Journal of Cave and Karst Studies 58(2):69-75 External links Actun Tunichil Muknal at TravelBelize.org Caves of Belize Maya sites in Belize Cayo District Cave sites in Mesoamerican archaeology