860-291780 - Tourists in the lava tunnels, Reunion Island, France

1184-7374 - Aerial of the Koko Oana underground lava tube, Anaa atoll, Tuamotu archipelago, French Polynesia, South Pacific, Pacific

1116-49670 - Wire coral goby (Bryaninops yongei) on wire coral (Cirrhipathes sp.), a relative of black coral.

1337-6 - A Lava fall pours from a lava tube 60 feet high, the heat and pressure of super heated ocean steam creates powerful explosions, Hawaii Volcanoes National Park, UNESCO World Heritage Site, Hawaii, United States of America, Pacific

832-389168 - Entrance to Thurston Lava Tube, Lava tube, Hawai'i Volcanoes National Park, Big Island, Hawaii

1320-72 - Lava Tube, Santa Cruz, Galapagos, UNESCO World Heritage Site, Ecuador, South America

1116-46540 - Mackerel Scad (Decapterus Macarellus) Schooled Off The Kona Coast, Kona, Island Of Hawaii, Hawaii, United States Of America

832-382419 - Water reflections in the cave Cueva de los Verdes, illuminations of the cave system of a lava tube designed by Cesar Manrique, Lanzarote, Canary Islands, Spain, Europe

832-382418 - Pool in the lava cave ""Jameos del Agua"", designed by Cesar Manrique, Lanzarote, Canary Islands, Spain, Europe

832-380070 - Swimming pool, lava cave Jameos de Aqua, by Cesar Manrique, Lanzarote, Canary Islands, Spain, Europe

733-6448 - Manjanggul Lava Tube, UNESCO World Heritage Site, Jeju Island, South Korea, Asia

733-6450 - Manjanggul Lava Tube, UNESCO World Heritage Site, Jeju Island, South Korea, Asia

733-6449 - Manjanggul Lava Tube, UNESCO World Heritage Site, Jeju Island, South Korea, Asia

816-6266 - Manjanggul longest lava tube system in the world on the island of Jejudo, UNESCO World Heritage Site, South Korea, Asia

816-6269 - Manjanggul longest lava tube system in the world on the island of Jejudo, UNESCO World Heritage Site, South Korea, Asia

816-6267 - Manjanggul longest lava tube system in the world on the island of Jejudo, UNESCO World Heritage Site, South Korea, Asia

816-6268 - Manjanggul longest lava tube system in the world on the island of Jejudo, UNESCO World Heritage Site, South Korea, Asia

1113-95771 - Canyoning in Lava Tubes, Tahiti, Society Islands, French Polynesia, Windward Islands, South Pacific

733-5745 - Raufarholsheillir lava tube cave system, Iceland, Polar Regions

817-415877 - Guests from the Lindblad Expedition ship National Geographic Endeavour explore a lava tube on Santa Cruz Island in the Galapagos Islands, Ecuador

1113-22810 - Diver at Caves of Lava Tubes, Cathedrals of Lanai, Maui, Hawaii, USA

1113-22807 - Diver at Caves of Lava Tubes, Cathedrals of Lanai, Maui, Hawaii, USA

1116-35930 - Hawaii, Big Island, Hawaii Volcanoes National Park, Molten lava seen through hole in lava tube.

29-5146 - Archway Cave, segment of very large lava cave, Undara Lava Tubes National Park, Queensland, Australia, Pacific

759-5978 - Diver at Caves of Lava Tubes, Cathedrals of Lanai, Maui, Hawaii, USA

759-5977 - Diver at Caves of Lava Tubes, Cathedrals of Lanai, Maui, Hawaii, USA

759-5976 - Diver at Caves of Lava Tubes, Cathedrals of Lanai, Maui, Hawaii, USA

797-3609 - Australia Western Australia Wagin Wave Rock - Eroded Lava Tube Antipodean Aussie Australian Oceania Oz

83-11859 - 'The Spouting Horn' on the south coast near Poipu, where sea swell is forced through an old lava tube, making a strange noise, Kauai, Hawaii, USA