Taken from the archives of the Great Lakes section of the epa.gov site.<a rel="nofollow" class="external autonumber" href="http://www.epa.gov/greatlakes/image/viz_iss3.html">[1]</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/62025628@N00">Thoth God of Knowledge</a> from Boston, United States
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/thoth-god/4126680647/">Dredging, Duluth, Minnesota-epa.gov</a>