A ship builder walks past a section of the Oasis Class 3 cruise ship at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. The Oasis-class III vessel is scheduled for delivery in mid-2016. (Photo by Stephane Mahe/Reuters)

“Left behind” children Luo Hongni, 11 (L) and brother Luo Gan,10, carry flowers to be used as feed while doing chores in the fields on December 18, 2016 in Anshun, China. Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. (Photo by Kevin Frayer/Getty Images)

Workers carve ice art works at Harbin Ice and Snow World one day before the 32th Harbin International Ice and Snow Festival in Harbin city, China's northern Heilongjiang province, 04 January 2016. The festival will run from 05 January to 05 February. (Photo by Wu Hong/EPA)

Dogs and their owners dressed in Halloween costumes parade during the annual Haute Dog Howl'oween event in Long Beach, California on October 30, 2016. The parade, which claims to be the largest Halloween dog event in the world, sees hundreds of dogs and their owners dressed in colorful costumes celebrating the festival. (Photo by Mark Ralston/AFP Photo)

Omani Tactical & Commando personnel are seen during the month-long GCC joint security exercise “Arabian Gulf Security 1” in Manama, Bahrain November 1, 2016. “Arabian Gulf Security 1” exercises will continue until mid-November with the participation of the UAE, Saudi Arabia, Oman, Qatar and Kuwait. (Photo by Hamad I. Mohammed/Reuters)

A displaced Iraqi boy leads his animals to safety after escaping from Islamic State controlled village of Abu Jarboa during clashes with IS militants near Mosul, Iraq November 1, 2016. (Photo by Ahmed Jadallah/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)

Fatima Rezai, 21, a female officer from the Afghan National Army (ANA) practices with a punch bag during an exercise session at at the Kabul Military Training Centre (KMTC) in Kabul, Afghanistan October 23, 2016. (Photo by Mohammad Ismail/Reuters)