The thick vegetation around a part of the "borrow pit" surrounding the Shark Valley observation tower in Everglades National Park, Florida.  This pond was created as a quarry for building the service road and the tower itself.
<a href="//commons.wikimedia.org/wiki/User:Domob" title="User:Domob">Daniel Kraft</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>