When a photo of a harbor seal swimming through an underwater kelp forest was shown to the judges of the Underwater Photography Contest by the University of Miami's Rosenstiel School of Marine and Atmospheric Science, they paused.
"The organizers would flash the photos in front of us," university scientist and contest judge Jiangang Luo told National Geographic, "and when that one showed up, it caught all of our attention."
Essentially, that is how the three judges agreed upon Kyle McBurnie's photo (above) becoming the contest's overall winner. Once you see a few other photos below, you'll see why it is such a difficult task selecting the best.
The annual Underwater Photography Contest for amateur photographers began in 2005 and has grown ever since, with more than 700 entries submitted from 23 countries in categories that included macro, wide angle, fish or marine animal portrait, and best student entry.
Take a look at some of the winning images, courtesy of the Rosenstiel School of Marine and Atmospheric Science:
See the entire list of 2013 winners, along with past winners, at the Rosenstiel School of Marine and Atmospheric Science website.