A heifer, tied with a rope, turns during “Toro de Cuerda” in the white village of Villaluenga del Rosario, southern Spain September 3, 2016. Dazzling clusters of cube-shaped houses perched on top of Andalusia's olive tree-studded mountains, the “Pueblos Blancos”, or white villages, of southern Spain are named for the lime wash the buildings are painted with to keep the interiors cool. The labyrinths of narrow alleyways are a throwback to when this region was known as Al-Andalus and was part of a medieval Muslim territory. While this region is stunningly beautiful and a big draw to tourists visiting the south of Spain, it is also one of the poorest areas in the country and has one of the highest unemployment rates in the European Union. (Photo by Marcelo del Pozo/Reuters)

Commuters hang off a local passenger train in the morning in Colombo, Sri Lanka September 8, 2016. (Photo by Dinuka Liyanawatte/Reuters)

Robot inventor Wu Yulu sits on a rickshaw driven by a robot which he invented in his village in rural Beijing's Tongzhou district, China, 17 November 2016. The 54-year-old Chinese farmer living in rural Beijing's Tongzhou district invented 63 robots in the past 30 years. Wu, who only received primary school education, plans to give up the agricultural work for his robot products. He regularly participates in exhibitions, transfers patent rights and teaches at the university to earn money. (Photo by Wu Hong/EPA)

A military guard carries flowers through the Cementerio Santa Ifigenia where the remains of former Cuban President Fidel Castro were entombed December 4, 2016 in Santiago de Cuba, Cuba. The tomb stands to the side of a memorial to the rebel soldiers killed in an attack that Castro led on Santiago's Moncada barracks on July 26, 1953, and in front of the mausoleum of Cuban national hero Jose Marti. (Photo by Chip Somodevilla/Getty Images)

A student from “the cliff village” in Atule'er climbs newly-constructed steel ladders after school to go home for holidays, in Liangshan Sichuan province, China, November 19, 2016. The steel ladders which replaced the unsafe vine ladders shortened the time taken for the children to go home, from three hours to two. (Photo by Reuters/Stringer)

A serviceman walks near an APC while a helicopter flies on the position of the Ukrainian troops in Donetsk region on August 9, 2014. Fighting with pro-Russian separatists in eastern Ukraine has left 13 troops dead in the last 24 hours, Ukraine's military said Saturday. (Photo by Anatolii Stepanov/AFP Photo)

A Uyghur boy sits atop a horse as he has his picture taken outside the Id Kah Mosque before the Eid holiday on July 28, 2014 in old Kashgar, Xinjiang Province, China. Nearly 100 people have been killed in unrest in the restive Xinjiang Province in the last week in what authorities say is terrorism but advocacy groups claim is a result of a government crackdown to silence opposition to its policies. China's Muslim Uyghur ethnic group faces cultural and religious restrictions by the Chinese government. Beijing says it is investing heavily in the Xinjiang region but Uyghurs are increasingly dissatisfied with the influx of Han Chinese and uneven economic development. (Photo by Kevin Frayer/Getty Images)

A man rides a motorcycle along a street in the snow in Altay, Xinjiang Uighur Autonomous region, February 9, 2016. (Photo by Reuters/Stringer)