In Hawaii, many lava flows form tubes that may extend for several kilometers. This is an efficient way for the lava to travel comparatively large distances without significant cooling. Thurston Lava Tube, located close to the summit of Kilauea Caldera, is a fine example of this type of landform. Here the tube is approximately 3 meters in diameter. Note two lava benches on the wall on the left.
Photograph courtesy of P. Mouginis-Mark.