Xibalba: The Maya Underworld (2013)

Filmed during a week-long trip to the cenotes (caverns) in Tulum, Mexico, diving seven different cenotes, from deep pit cenotes with clouds of hydrogen sulphide, to spectacular cave formations, haloclines and beautiful root structures with aquatic life. This film is about Xibalba, which translates as 'place of fear' to the Maya, who believed that the cenotes were gateways to Xibalba, the underworld.