This photo provided by NASA shows a full moon rising behind the United Launch Alliance Atlas V rocket with NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft onboard at the Cape Canaveral Air Force Station Space Launch Complex 41, Sunday, November 17, 2013, Cape Canaveral, Florida. NASA's next Mars-bound spacecraft, the Mars Atmosphere and Volatile Evolution, or MAVEN, is the first spacecraft devoted to exploring and understanding the Martian upper atmosphere. (Photo by Bill Ingalls/AP Photo/NASA)

City buildings stand beyond the giant excavated hole left by the Mir mine, a former open pit diamond mine, in Mirny, Russia, on Tuesday, November 12, 2013. OAO Alrosa, the world's largest diamond producer, raised about $1.3 billion in an oversubscribed share sale from investors including Oppenheimer Funds Inc. and Lazard Ltd.'s asset-management unit, First Deputy Prime Minister Igor Shuvalov said. (Photo by Andrey Rudakov/Bloomberg)

An Army Sikorsky VH-34s Choctaw helicopter once used to transport President Dwight D. Eisenhower sits in a field at the 309th Aerospace Maintenance and Regeneration Group boneyard Thursday, May 14, 2015 at Davis-Monthan Air Force Base in Tucson, Ariz. President Eisenhower became the first chief executive to be transported by helicopter. Presidents Eisenhower and John F. Kennedy were transported in VH-34 helicopters and VH-34's served as “Army One” from 1958 through 1963. (Photo by Matt York/AP Photo)

Birds fly over the Atomic Bomb Dome in Hiroshima, western Japan July 29, 2015. On August 6, 1945, the U.S. dropped the atomic bomb on Hiroshima, killing about 140,000 by the end of the year in a city of 350,000 residents, in the world's first nuclear attack. Three days later, a second atomic bomb was dropped on Nagasaki. Influenced by the shadows scorched into outdoor surfaces by the heat of the blasts 70 years ago, Reuters photographer Issei Kato pays homage to survivors, residents and historic buildings in both cities in a personal project that captures the shadows of today. (Photo by Issei Kato/Reuters)

Students from St Andrew's University indulge in a tradition of covering themselves with foam to honour the “academic family” on October 20, 2014, in St Andrews, Scotland. Every November the “raisin weekend” which is held in the university's Lower College Lawn, is celebrated and a gift of raisins (now foam) is traditionally given by first year students to their elders as a thank you for their guidance and in exchange they receive a receipt in Latin. (Photo by Jeff J. Mitchell/Getty Images)

The 1963 Batmobile is shown in this photo released by Heritage Auctions, HA.com December 5, 2014. The earliest known officially licensed car of comic book superhero Batman is up for auction on Saturday. The 1963 Batmobile is believed to be the first custom car to be licensed as Batman's swanky ride and could fetch up to $500,000, according to officials with Dallas-based Heritage Auctions. The opening bid is $90,000. (Photo by Reuters/Heritage Auctions)

A girl in a vamire costume poses for pictures during the traditional park picnic on the first day of the annual Wave-Gotik Treffen, or Wave and Goth Festival, on May 17, 2013 in Leipzig, Germany. The four-day festival, in which elaborate fashion is a must, brings together over 20,000 Wave, Goth and steam punk enthusiasts from all over the world for concerts, readings, films, a Middle Ages market and workshops. (Photo by Marco Prosch)

Pope Francis greets the crowd from his popemobile in downtown Rio de Janeiro. Pope Francis touched down in Rio de Janeiro on Monday, starting his first foreign trip as pontiff and a weeklong series of events expected to attract more than a million people to a gathering of young faithful in Brazil, home to the world's largest Roman Catholic population. (Photo by Ueslei Marcelino/Reuters)