Located in Hawaii Volcanoes National Park, on the Island of Hawaiʻi, the Thurston Lava Tube is one of the main attractions for visitors as they explore the park. As lava flows the outer crust begins to harden while the inner lava continues to flow. Once the flow stops, the tunnel formation remains. Like veins leading from the central 'heart' of the volcano, lava tubes direct molten rock toward the ocean.