The Acheron, Greece -- Cape Matapan, Greece -- Pluto's Gate, Turkey -- Cave of the Sibyl, Italy -- Lake Avernus, Italy -- Lacus Curtius, Italy -- Oweynagat Cave, Ireland -- Hill of Ward and Hill of Tara, Ireland -- St. Patrick's Purgatory, Ireland -- Valley of Hinnom, Israel -- Houska Castle, Czechia -- Hekla Volcano, Iceland -- Well of Hell, Yemen -- Mount Osore, Japan -- Cape Reinga, New Zealand -- Maya Cenotes, Mexico -- Actun Tunichil Muknal Cave, Belize -- Masaya Volcano, Nicaragua -- Seven Gates of Guinee, Louisiana, U.S.A. - Seven Gates of Hell, Pennyslvania, U.S.A. -- Gates of Hell, Turkmenistan - Hell's Gate, California, U.S.A. - Hell, Michigan, U.S.A. -- Hell, Grand Cayman, Cayman Islands - The World's Rare Lakes of Fire -- Phlegrean Fields, Italy -- Naples, Italy -- Pompeii and Herculaneum, Italy - Deadvlei (Dead Valley), Namibia -- Dead Sea, Jordan and Israel -- The Hells of Beppus, Japan -- Blood Falls, Antarctica -- Haw Par Villa, Singapore -- Rotorua, New Zealand -- Wai-O-tapu Scenic Reserve, New Zealand -- Waimangu Volcanic Valley, New Zealand -- Yellowstone National Park, Wyoming, Montana, and Idaho, U.S.A. -- Danakil Depression and Erta Ale, Ethiopia -- Cave of the Crystals, Mexico -- Gomantong Caves, Malaysia -- Waitomo Glowworm Caves, New Zealand -- Tsingy de Bemaraha, Madagascar -- Deception Island, Antarctica -- Craters of the Moon, Idaho, U.S.A. -- Lake Natron, Tanzania -- Skull Rock, Australia -- Hodge Close Quarrym England, U.K. -- Boiling River, Peru -- Lake Maracaibo, Venezuela -- Kawah Ijen Volcano, Indonesia -- Fengdu Ghost City, China -- Kasanka National Park, Zambia -- Bracken Cave, Texas, U.S.A. -- Cape York, Queensland, Australia.