<p><i>This month, our Photo of the Day editor shares why she chose the shots that you liked best.</i></p> <p>In winter young <a href="http://animals.nationalgeographic.com/animals/fish/whale-shark/?source=podinline">whale sharks</a> come to feed on plankton in the nutrient-rich waters of the Gulf of Tadjoura, off the arid coast of <a href="http://travel.nationalgeographic.com/travel/countries/djibouti-guide/?source=podinline">Djibouti</a>. The world's largest fish—weighing more than an elephant—is becoming a symbol of Arabia's bountiful, but largely unprotected, marine heritage.</p> <p><i>See more <a href="http://ngm.nationalgeographic.com/2012/03/arabian-seas/peschak-photography?source=podrelated">pictures</a> from the March 2012 feature <a href="http://ngm.nationalgeographic.com/2012/03/arabian-seas/warne-text?source=podrelated">story</a>, "The Seas of Arabia."</i></p> <p><b>What Made This a Photo of the Day</b></p> <p>I'm often drawn to over/under shots like these, in which you get a glimpse of a hidden world just below the surface of the waves. And in this case, the immediacy of coming face to face with such a beautiful creature is thrilling—as is imagining yourself in the water with it. <i>—Alexa Keefe, Photo of the Day editor</i></p>