Thurston Lava Tube

East of the intersection with Chain of Craters Rd you enter the rain forest of native tree ferns and ohia that covers Kilauea's windward slope. Thurston Lava Tube is the endpoint of an enjoyable short walk through a bird-filled ohia forest (it's a good place to spot the red-bodied 'apapane, a native honeycreeper). The lava tube itself is enormous - big enough for your car - and a short initial section is lighted. Does get crowded.

Lava tubes are formed when the outer crust of a river of lava starts to harden but the liquid lava beneath the surface continues to flow through. After the flow has drained out, the hard shell remains. Eastern Hawai'i is riddled with lava tubes, but this may be the grandest example. The tube extends for quite a ways beyond the lighted area; with a flashlight it's easy to keep going - and highly recommended.