A leopard skin burns as Indian officials and activists burn wildlife contraband including tiger and leopard skins, and bones as part of a campaign to save the tiger in Mumbai, India, Tuesday, July 30, 2013. Despite conservation efforts, tiger numbers in India have declined due to rampant poaching of the cats for their valuable pelts and body parts that are highly prized in traditional Chinese medicine. (Photo by Rafiq Maqbool/AP Photo)

A competitor poses before the Tough Guy Challenge endurance race on January 27, 2013 in Telford, England. Every year thousands of people run the 8 mile assault course which involves freezing temperatures, fire and ice. (Photo by Michael Regan)

An infrared portrait from NASA's Spitzer Space Telescope which shows generations of stars is seen in this undated NASA handout image released February 14, 2013. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. (Photo by NASA/Reuters/JPL-Caltech/Harvard-Smithsonian/Handout)

Toyota revealed its i-Road concept, a three-wheeled all-electric motorcycle of sorts that seats two. The unique design is only 33 inches wide, which would make it tops in buzzing in through and around traffic. An Active Lean system tilts the i-Road through corners like a motorbike, while the cabin (which seats two in a tandem layout) is fully enclosed. Maximum range is about 30 miles. (Photo by Luis Fernando Ramos/G1)

A schoolgirl collects rubbish from Karachi's Clifton beach early morning April 22, 2013, during a cleaning campaign as part of the commemoration of Earth Day. (Photo by Akhtar Soomro/Reuters)