A good view of such a lava tube is shown below.
There is a lava tube, just one, under the site.
Or else this was one hell of a lava tube.
They set up a camp back out of the weather in an old lava tube.
The cave is an excellent example of a lava tube.
The major caves of the Horse system are lava tubes.
You can peer into a lava tube with its own ecosystem.
They emerged from the lava tube, into a dazzling morning.
One such lava tube was discovered in early 2009.
It is also the largest lava tube in Jeju island.