People board a train at the West Railway Station on January 7, 2012 in Beijing, China. China's railways are bracing themselves as millions of migrant labourers are set to leave cities for their native villages to celebrate the Chinese New Year. (Photo by Lintao Zhang/Getty Images)

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)

Local villagers ride a local coal powered steam train on March 27, 2015 at a station in the town of Shixi , Sichuan Province, in Southern China. While China boasts the world's most extensive high-speed rail infrastructure with over 16,000 kilometers of track, the Shixi-Bagou railway is still a primary connection for local villagers between towns and is kept alive by tourist cars carrying passengers for ten times the price. The rail line came into service in the late 1950s and the train was initially used to transport coal from a now-shuttered mine before passenger carriages were added. (Photo by Kevin Frayer/Getty Images)

Skeleton bodypainting in Chimbu tribe. Village Mindima, Simbu (a Highlands Region province in Papua New Guinea), September 14, 2009. (Photo by Rita Willaert; Source: Flickr)

Burundian refugees gather on the shores of Lake Tanganyika in Kagunga village in Kigoma region in western Tanzania with their belongings, as they wait for MV Liemba to transport them to Kigoma township, May 17, 2015. Burundi's embattled President Pierre Nkurunziza sacked his defense and foreign ministers on Monday, five days after surviving an attempted coup by generals opposed to his bid for a third term in office. (Photo by Thomas Mukoya/Reuters)

A Rohingya migrant woman, who arrived in Indonesia by boat, carries a bottle of drinking water inside a temporary compound for refugees in Kuala Cangkoi village in Lhoksukon, Indonesia's Aceh Province May 17, 2015. (Photo by Reuters/Beawiharta)

A farmer works in a paddy field at Reba Maheswar village, 56 kilometers (35 miles) east of Gauhati, India, Friday, July 3, 2015. Rice is one of the most important food crops of India and about 4,000 different varieties are grown in different parts of the country. (Photo by Anupam Nath/AP Photo)

Combine harvesters work on a wheat field of the Solgonskoye farming company near the village of Talniki, southwest from Siberian city of Krasnoyarsk, Russia, August 27, 2015. Russia, one of the world's top wheat exporters, will harvest its third-largest grain crop in post-Soviet history this year, leading Russian consultancy SovEcon said on August 27 after upgrading its forecast. (Photo by Ilya Naymushin/Reuters)