Exit of the Thurston Lava Tube, Kilauea, Hawaii, United States
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/86265563@N00">LuxTonnerre</a> from Munich, Germany
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/luxtonnerre/2926417023/">Flickr</a>