Lava tubes

France

• 
  Piton Chisny, Réunion
• 
  Lava tube at Saint-Gilles on the roadside, Réunion
• 
  Decimetric lava tube, Piton de la Fournaise, Réunion
• 
  Exploring the lava tubes of the 2004's eruption of the peak of Furnace, Réunion

Iceland

• 
  Surtshellir
• 
  Surtshellir
• 
  Víðgelmir
• 
  Víðgelmir
• 
  Víðgelmir
• 
  Víðgelmir
• 
  Víðgelmir
• 
  Dimmuborgir

Italy

• 
  Etna
• 
  Etna

Japan

• 
  Lake Saiko Bat Cave
• 
  Lake Saiko Bat Cave

Korea

• 
  Manjanggul

Portugal

• 
  Gruta das Torres (Pico Island), Azores
• 
  lavacicles, Gruta das Torres (Pico Island), Azores

United States of America

California

• 
  collapsed ceiling, Lava Beds National Monument
• 
  illuminated lava tube, Lava Beds National Monument
• 
  illuminated lava tube, Lava Beds National Monument
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  Ferncave, Lava Beds National Monument
• 
  Blue Grotto, Lava Beds National Monument
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  Lava Beds National Monument
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  Valentine Cave, Lava Beds National Monument
• 
  lavacicles in Valentine Cave, Lava Beds National Monument
• 
  lavacicles in Mushpot Cave, Lava Beds National Monument

Hawaii

• 
• 
  Thurston lava tube (Big Island)
• 
  Stalactites (shark teeth)
• 
  Kupaianaha lava pond
• 
  helictite
• 
  tubular stalactites
• 
  Haleakala National Park
• 
  active lava tube with lava stalactites forming on the roof of the tube

Idaho

• 
  Wilson Butte Cave
• 
  Wilson Butte Cave
• 
  Wilson Butte Cave
• 
  Craters of the Moon National Monument

Wyoming

• 
  Lava tube opening in Devils Half Acre, Yellowstone National Park

other

• 
  Spain
• 
  splash lavacicles
• 
  Australia