A student uses a ruler to measure the distance between forks before a formal dinner at The International Butler Academy China on September 16, 2014 in Chengdu, China. Over the last several years, there has been a surge in demand among China's wealthy for Western-trained butlers, with many academies seeing large portions of their graduating classes hired by Chinese families or companies. (Photo by Taylor Weidman/Getty Images)

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)

Elementary school children play outside their classrooms as mount Sinabung volcano spews thick volcanic ash in the background on February 10, 2017 in Karo, Indonesia. Mount Sinabung is one of the most active volcanoes in Indonesia and last erupted in May 2016, killing seven people. (Photo by Albert Damanik/Barcroft Images)

Zulmira Jesus poses for a portrait at a street in Povoa de Agracoes, near Chaves, Portugal April 19, 2016. In the villages of Agracoes and Povoa de Agracoe, the steady drip-drip of emigration has brought down population numbers from more than 50 residents to fewer than a dozen each. These remaining villagers share the same glum acceptance that, after they have gone, their villages will die out too. It is the same desolate picture in scores of other backwater settlements in Portugal's interior, north to south. (Photo by Rafael Marchante/Reuters)

A girl salutes to visitors before a show at the Mangyongdae Children's Palace in central Pyongyang, North Korea May 5, 2016. Pyongyang held a gala of song and dance performances by local school children on May 5 for visiting delegations of foreign journalists and tourists at the Mangyongdae Children's Palace. The event included orchestral, choir, and acrobatic performances, many of them with political undertones. The Seventh Worker's Party Congress commences on May 6, 2016. (Photo by Damir Sagolj/Reuters)

A young Thai man jumps in the air and cheers as his rocket takes off at the Bun Bang Fai Rocket Festival on May 10, 2015 in Yasothon, Thailand. During the Bun Bang Fai rocket festival, Thai residents launch enormous home-made rockets into the air to gain Buddhist merit and to celebrate the beginning of the rainy season. (Photo by Taylor Weidman/Getty Images)

Participants, one of them loosing balance, jump in a sack race at a shopping center in Paris to win a 500 euros voucher (537 USD), on the first day of the winter sales in Paris, France, Wednesday, January 6 , 2016. The five-week 2016 winter sales start everywhere across France on Wednesday Jan. 6 and end on Feb. 16. (Photo by Francois Mori/AP Photo)

A rebel fighter carries his weapon as he moves through a hole in a wall in the old city of Aleppo near the frontline against forces loyal to Syria's President Bashar al-Assad December 28, 2014. (Photo by Jalal Al-Mamo/Reuters)