<p>Hoping to inspire a freeze on shark hunting, Australia's Melbourne Aquarium has put a 15-foot (4.5-meter) great hammerhead shark (pictured July 12) on ice.</p><p>Reproducing only once every two years, the species is especially vulnerable to overfishing and has been <a href="http://www.iucnredlist.org/apps/redlist/static/categories_criteria_3_1">designated endangered by the International Union for Conservation of Nature</a>, meaning the great hammerhead faces a very high risk of extinction in the wild.</p><p>Commercial fishers accidentally caught the now frozen fish off Australia in March 2010, illustrating a key threat to sharks today. Off Africa alone, for example, <a href="http://news.nationalgeographic.com/news/2007/04/070417-shark-fishing.html">more than eight million sharks are accidentally killed each year</a>, experts reported in 2007.</p><p><strong>Why We Love It</strong></p><p>"The subdued palette lets the shark's personality shine through."<em>—Chris Combs, news photo editor</em></p><p>"The angle and lighting of this photo make something already bizarre even stranger. Is it a shark or an alien life-form?"<em>—Monica C. Corcoran, senior photo editor</em></p>