Members of the New People's Army (NPA) female guerrillas perform a cultural show during the release of a Philippines army soldier in Sugbongcogon town, Misamis Oriental, southern Philippines, November 20, 2015. NPA spokesperson Allan Juanito warned that they will seize more soldiers to exchange them with the government as "Prisoners of war". (Photo by Froilan Gallardo/Reuters)

A bride gets ready during a mass wedding ceremony in the old quarters of Delhi February 20, 2015. A total of 12 couples took their wedding vows on Friday during the mass wedding ceremony organised by a Hindu religious organisation, an organiser said. (Photo by Ahmad Masood/Reuters)

A boy looks for sellable materials close to the burning garbage in the permanent waste land under Sylhet City Corporation for a living, on January 15, 2015. (Photo by Md. Akhlas Uddin/Pacific Press)

The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

A man steers with his legs while riding a motorcycle on a road in Vietnam's northern Hoa Binh province, outside Hanoi, October 15, 2015. (Photo by Reuters/Kham)

An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

Women, dressed in traditional Japanese kimonos, cross a street in Kyoto, western Japan November 19, 2014. (Photo by Thomas Peter/Reuters)

Lazar and his sister Andjelka sit by a candle in their home in the eastern Serbian town of Majdanpek, December 4, 2014. Electricity workers in Serbia struggled through snow, ice and treacherous terrain on Thursday to restore electricity to an eastern town left shivering without power, heating or running water for a fourth day. (Photo by Marko Djurica/Reuters)