Inside Old Mans Cave, Hocking Hills State Park, Ohio. This photo is an HDR composite of 6 different exposures.
<a href="//commons.wikimedia.org/wiki/User:Sixflashphoto" title="User:Sixflashphoto">Sixflashphoto</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>