The Aletsch Glacier is pictured at dusk in Fiesch, Switzerland, August 11, 2015. One of Europe's biggest glaciers, the Great Aletsch coils 23 km (14 miles) through the Swiss Alps – and yet this mighty river of ice could almost vanish in the lifetimes of people born today because of climate change. The glacier, 900 metres (2,950 feet) thick at one point, has retreated about 3 km (1.9 miles) since 1870 and that pace is quickening. (Photo by Denis Balibouse/Reuters)

A hyena eyes a herd of zebra at Lake Nakuru National Park, Kenya, August 19, 2015. The Park is home to some of the world's most majestic wildlife including lions, rhinos, zebras and flamingos. The scenery is stunning, from forests of acacia trees to animals congregating at the shores to drink. UNESCO says that with rapid population growth nearby, the area is under "considerable threat from surrounding pressures," particularly deforestation, a contributing factor in floods. (Photo by Joe Penney/Reuters)

A worker looks on with his camel as he waits for tourists at the Giza Pyramids on the outskirts of Cairo, Egypt, November 8, 2015. Egypt's Tourism Minister Hesham Zaazou said Cairo regretted the suspension of flights and was doing all it could to secure its airports and tourist sites, adding that he would fly to Sharm al-Sheikh to oversee measures to support tourists there. (Photo by Amr Abdallah Dalsh/Reuters)

A model wears a bazin dress made by designer Fadi Maiga in Bamako, Mali, October 21, 2015. Gasps of delight filled the convention hall as models, decked out in Mali's signature bazin fabric in crimson reds, indigoes and neon greens, strutted the catwalk while musicians from across the West African nation provided the soundtrack. (Photo by Joe Penney/Reuters)

Members of the Moranbong Band from North Korea wait inside the lobby of a hotel in central Beijing, China, December 11, 2015. North Korea's premier pop group, the all-girl Moranbong band formed by leader Kim Jong-Un, is electrifying audiences in China in shows aimed at harmonising out-of-tune ties between the traditional allies, reports and the venue said on December 9 – but tickets are not available to the public. (Photo by Reuters/Stringer)

A Santa Claus taking a selfie on a surfboard is seen in the yard of a home in the Sleepy Hollow area of Torrance, California, United States, December 15, 2015. In many neighborhoods of Los Angeles, homeowners compete for the most lavish and creative holiday light displays. Torrance's Sleepy Hollow is one such neighborhood where every home outdoes the next: surfing Santas, life-size nativity scenes, ferris wheels, and giant inflatable snowmen line the lawns on every street. (Photo by Lucy Nicholson/Reuters)

People look at a RoboThespian humanoid robot at the Tami Intelligence Technology stall at the WRC 2016 World Robot Conference in Beijing, China, October 21, 2016. The conference showcased China's burgeoning robot industry as the nation seeks to increase the use of robots in its manufacturing and service industries. (Photo by Thomas Peter/Reuters)

Passengers from a passing train watch as rescue workers search a train which crashed in Karachi, Pakistan, November 3, 2016. At least 17 people have been killed and dozens more injured after two trains carrying hundreds of passengers collided in Pakistan's southern port city of Karachi, officials said. (Photo by Akhtar Soomro/Reuters)