Venturing into a lava tube

Kaumana Caves on the Big Island of Hawaii.

This cave is actually a skylight in a 25-mile long lava tube that was created by an 1881 flow from Mauna Loa. Located near Hilo, the opening to the tube is overgrown with plants due to the ambundant rain on this side of the island. Long, thin roots reach all the way down to the floor of the lava tube.