A protest of the Keystone XL pipeline last March along its proposed route near Bradshaw, Nebraska. NH/AP hide caption

itoggle caption NH/AP

A tasseled wobbegong shark (top) lies on the seafloor with the head of a brown-banded bamboo shark in its mouth on the fringing reef of Great Keppel Island on Australia's Great Barrier Reef in August 2011. Reuters/Landov hide caption

itoggle caption Reuters/Landov

Fireworks explode in a Shanghai street on Thursday, the eve of the Lunar New Year. Setting off firecrackers is meant to ward off evil spirits and bring good luck. But many Chinese say they won't buy firecrackers this year, owing to growing worries about air quality. Peter Parks/AFP/Getty Images hide caption

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Workers inspect an area near storage tanks where a chemical leaked into the Elk River at Freedom Industries storage facility in Charleston, W.Va., on Jan. 13. It is still unclear exactly how much of the chemicals leaked into the area's water supply. Steve Helber/AP hide caption

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Magellanic penguins strut their stuff on the rocky shoreline of Argentina's Punta Tombo, home to the largest colony of the birds in the world. Craig Lovell/Corbis hide caption

itoggle caption Craig Lovell/Corbis

SpaceX's Dragon spacecraft atop rocket Falcon 9 lifts off from Cape Canaveral in Florida in May 2012. The launch made SpaceX the first commercial company to send a spacecraft to the International Space Station. Roberto Gonzalez/Getty Images hide caption

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Gas flaring near Highway 85 southwest of Williston. Analysts estimate that almost 30 percent of the gas being produced in the state is burned off. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Jonathan Steele, owner of Bluegrass Kitchen, fills a jug with bottled water from a tank he installed in the back of his Charleston restaurant. Steve Helber/AP hide caption

itoggle caption Steve Helber/AP

A boat skims through the melting ice in the Ilulissat fjord in August 2008, on the western coast of Greenland. Steen Ulrik Johannessen/AFP/Getty Images hide caption

itoggle caption Steen Ulrik Johannessen/AFP/Getty Images

Young survivors of Typhoon Haiyan brave December rain as they ask for gifts from residents in the streets of Tacloban, the Philippines. Months after the storm, cleanup is still ongoing and many of the more than 6,000 dead have yet to be identified. Ted Aljibe /AFP/Getty Images hide caption

itoggle caption Ted Aljibe /AFP/Getty Images