An Afghan refugee girl shows her younger brother a calf in a slum on the outskirts of Islamabad, Pakistan, Friday, February 6, 2015. (Photo by Muhammed Muheisen/AP Photo)

Julian, left, is photographed by his mother with friend Gianluca, right, under water at a public pool in Gelsenkirchen, Germany, on a hot Friday, July 3, 2015. Germany faces a heat wave with temperatures up to 38 degrees Celsius (100 degrees Fahrenheit) at the weekend. (Photo by Martin Meissner/AP Photo)

Cycling jerseys, part of a collection belonging to French cycling fan Gerald, hang from a line during the 4th stage of the Tour de France cycling race from Seraing in Belgium to Cambrai in France, July 7, 2015. Photographing the Tour de France cycling race comes with highs and lows: the buzz from capturing just the right image, the tedium of long journeys, the painstaking set-up of equipment, the breath-taking scenery. Reuters photographers have worked not only to capture the thrills and spills on the roads and mountain passes. They have also shot a set of pictures showing their own quirky view from behind the scenes as they travelled through the Netherlands, Belgium and France. (Photo by Eric Gaillard/Reuters)

“NASA's Mars rover Opportunity just celebrated its ninth anniversary on Mars – a mission that was originally meant to last just 90 days...” – The Atlantic. Photo: NASA's rover Opportunity visits Victoria Crater, viewed from orbit by the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter in october of 2006. Opportunity is a small dot on the crater's lip, at top right. Opportunity first reached the crater's rim on September 27, 2006. (Photo by NASA/JPL-Caltech/University of Arizona via The Atlantic)

A Rohingya Muslim from Myanmar (R), who tried to cross the Naf river into Bangladesh to escape sectarian violence, cries near his family in a Bangladeshi Coast guard station in Teknaf on June 19, 2012, before being sent back to Myanmar. (Photo by Munir Uz Zaman/AFP Photo)

Britain's skip Eve Muirhead, right, embraces Anna Sloan after defeating Switzerland to win the women's curling bronze medal at the 2014 Winter Olympics, Thursday, February 20, 2014, in Sochi, Russia. (Photo by Robert F. Bukaty/AP Photo)

Beryl Lipton, left, douses Matt Lee during the ice bucket challenge at Boston's Copley Square, Thursday, August 7, 2014 to raise funds and awareness for ALS. The idea is: pay up for charity or get doused. The fund-raising phenomenon is catching on fast, propelled by popular videos of the dunkers and the dunked – including famous athletes and entertainers – posted on social media sites. And the challenges are raising tens of thousands of dollars and immeasurable awareness for causes from ALS to breast cancer to a camp for kids who've lost a father to war. (Photo by Elise Amendola/AP Photo)