Students training to be flight attendants hold books on their heads, chopsticks in their mouths, and papers in between their knees, as they take part in a standing posture practice at a vocational school in Shijiazhuang, Hebei province, China May 4, 2017. (Photo by Reuters/Stringer)

Belly dancer Nagwa Fouad sailing on the river Nile, 1972. Egypt is one of 23 countries represented at the Dubai Photo Exhibition, showing off photography that dates to the 1920s. Dubai Photo Exhibition is in various venues of Dubai’s design district from 16-19 March. (Photo by Farouk Ibrahim)

In this Tuesday, March 10, 2015 photo, rime ice covers rocks on the summit of Mount Washington in New Hampshire. Rime ice occurs when freezing fog hits stationary objects in frigid conditions. (Photo by Robert F. Bukaty/AP Photo)

Sukaregang in Garut district, West Java, has long been a bustling center for Indonesia's leather trade, with some shops producing and selling various goods – including bags, shoes and jackets – since the 1940s. The industrial area is also a major supplier for high-end brands from across the globe, catering to the fashion, auto and motor-sports industry. Here: a man walks across a vat of water used to wash the hide. (Photo by Rezza Estily/JG Photo)

Chief priest Gbenga Saala raises a cutlass to kill a dog during an annual prayer and sacrifice celebration of the iron god Ogun in Abuja, Nigeria, June 23, 2015. Every year worshippers offer a dog as sacrifice to Ogun, a traditional Nigerian deity, in hope of an auspicious year ahead. Taxi drivers, blacksmiths, panel beaters and mechanics – trades that depend on metal for their livelihood – pay homage to Ogun, led by high priest Gbenga Saala. As part of the ceremony, the priest pours the dog’s blood on symbols of these workers’ trade: keys, spanners and other tools piled up in a metal barrel. (Photo by Afolabi Sotunde/Reuters)

Residents wade across floodwaters after a week typhoon Koppu battered Calumpit town, Bulacan province, north of Manila October 24, 2015. Typhoon Koppu, that dumped heavy rains on the northern Philippines, killing 58 people as it flattened houses and destroyed crops, was petering out on Wednesday, weather officials said. (Photo by Romeo Ranoco/Reuters)

Haitian policemen arrest a demonstrator with machetes at the end of a march, in Port-au-Prince, on November 26, 2015. Supporters of Fanmi Lavalas and Petit Dessalines political parties marched to protest against the results given by the Provisional Electoral Council (CEP), against the Haitian President Michel Martelly, and against the candidate of the ruling party Jovenel Moise. Provisional Electoral Council (CEP) confirmed this week that Haiti's presidential election will go to a runoff on December 27, between ruling party candidate Jovenel Moise and Jude Celestin, close to former president Rene Preval. (Photo by Hector Retamal/AFP Photo)

People hold out money as butchers sell their remaining produce of the year at discounted prices during the traditional Christmas Eve auction at Smithfield's market in London December 24, 2015. (Photo by Neil Hall/Reuters)