Thurston Lava Tube, Lava tube in Hawaii Volcanoes National Park, United States.

Thurston Lava Tube, called Nāhuku in Hawaiian, is a roughly circular lava tube on the east flank of Kīlauea in Hawaii Volcanoes National Park. Its floor, walls and ceiling are smooth, and the walls still show the high-lava mark of the flow that filled the passage. Only the first 150 metres are lit; the rest requires a torch and a permit from park staff.

The cave formed about 500 years ago during volcanic activity as lava flowed beneath the ground. Newspaper publisher Lorrin Thurston discovered it in 1913 and brought attention to this natural wonder.

The Hawaiian name Nāhuku refers to the bumps and ridges on the cave walls, shaped by cooling lava. Lorrin Thurston, a Hawaiian journalist, reached the passage in 1913; lava stalactites still hung from the ceiling then, but early visitors carried them off as souvenirs.

The cave is easy to visit during daylight hours since artificial lighting illuminates the passage. For visits in early morning or evening, bring your own light source to explore safely.

Lorrin Thurston found the cave in 1913, when lava stalactites still hung from its ceiling; early visitors carried them off as souvenirs, so none remain. Tree roots from the forest above reach through the rock and hang down inside, and they are the only food for the cave's insects and spiders.