In this Monday, March 16, 2015 photo, Syrian refugee Samira Helal, 17, who is two months pregnant, poses for a portrait at inside her tent at an informal tented settlement near the Syrian border, on the outskirts of Mafraq, Jordan. Nearly 3.8 million Syrians have fled their country and are now registered as refugees, according to the U.N. Most face increasingly desperate circumstances. (Photo by Muhammed Muheisen/AP Photo)

In this photo taken on Saturday, April, 4, 2015, a bear chews on a corncob at a shelter that attracts hundreds of visitors and volunteers from around the world every year, in Kutarevo, Croatia. Over a decade ago, Ivan Crnkovic-Pavenka, a retired Croatian social worker decided to help bears become “ambassadors of the wilderness” among people and set up a unique shelter for brown bears in the idyllic mountain village of Kutarevo in central Croatia, where eight bears currently live in two huge enclosures. (Photo by Amel Emric/AP Photo)

Master of throat singing (or Khoomei) Aikhan Orzhak (L) and model Choigana Kertek, dressed in traditional costume, perform during sunset at the Aldyn Bulak area on the bank of the Yenisei River outside the village of Ust-Elegest in Tuva region, Southern Siberia, Russia, October 7, 2015. The region is inhabited by Tuvans, historically cattle-herding nomads, who nowadays practise two main confessions – Buddhism and Shamanism. (Photo by Ilya Naymushin/Reuters)

A Chinese exhibitor checks lighting products at a booth during the China Import and Export Fair, also known as Canton Fair, in the southern Chinese city of Guangzhou October 15, 2015. Around two thirds of exporters at China's largest trade fair expect the slowdown in their markets to persist for at least six months, a Reuters poll has found, with the country expected to announce its slowest economic growth in decades early next week. (Photo by Bobby Yip/Reuters)

Marion (L) and Nikola (R), members of the Sport Saber League, pose with their light sabers in front of the Eiffel tower in Paris, France, November 26, 2015. Three "Star Wars" fans opened the French Academy of the Sport Saber League in September 2015 due to the increase interest for light saber fighting and the upcoming movie "The Force Awakens" which will premier in Paris, December 16th, two days before its worldwide official release. (Photo by Charles Platiau/Reuters)

Igor Perne (L), 53, an electronic engineer and a member of the International Virtual Aviation Organisation (IVAO), and fellow virtual pilot Franc Lavric gesture for the camera before taking off on a virtual flight in a flight simulator in Nova Vas, Slovenia November 13, 2014. In 2011, Perne, a lifelong flying enthusiast, bought parts of a written-off Cyprus Airways airliner and then spent two and a half years turning the entire nose of the scrapped aircraft into an elaborate flight simulator. (Photo by Srdjan Zivulovic/Reuters)

Revelers participate in the traditional Bloco da Lama (Mud block) carnival in Parati, Rio de Janeiro State, Brazil, on February 9, 2013. The event, which was begun by two men in a playful manner in 1986, has now become a traditional carnival in which participants disguised as primitives with rags, lianas or skulls and bones, dive in the mud. (Photo by Victor Moriyama/AFP Photo)

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)