Two teenage girls examining un-illuminated parts of <a href="//commons.wikimedia.org/wiki/Category:M%C3%B8nsted_Limestone_Mine" title="Category:Mønsted Limestone Mine">Mønsted Limestone Mine</a> using their smart phone lights as illumination. Their light trails are reflected in the water. Long exposure shot of 30 seconds.
<a href="//commons.wikimedia.org/wiki/User:Slaunger" title="User:Slaunger">Slaunger</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>