In this photograph taken on October 4, 2016, an Afghan baker prepares bread at his shop as he waits for customers in Lashkar Gah, the capital city of Helmand province. For years Helmand was the centerpiece of the Western military intervention in Afghanistan only for it to slip deeper into a quagmire of instability, with almost the entire southern province teetering on the verge of collapse. Intensified fighting has killed hundreds and forced thousands to flee to besieged capital Lashkar Gah, sparking a humanitarian crisis as the city – one of the last government- held enclaves – risks falling to the Taliban' s repeated ferocious assaults. (Photo by Wakil Kohsar/AFP Photo)

A leader “Rolli” of a yodel group “Schuppel” runs in the snow in front of a farmstead during the “Silvesterchlausen” in the early morning in Urnaesch in the Swiss canton Appenzell Ausserroden on January 13, 2017. (Photo by Michael Buholzer/AFP Photo)

Sheep walk as they are herded to summer pastures in Serra da Estrela, near Seia, Portugal June 27, 2015. In late June, shepherds young and old in the Seia region of central Portugal start guiding sheep, goats and cattle to the Serra da Estrela, the country’s highest mountains, in search of better pastures. There they stay until the end of September. Modern-day shepherds may have mobile phones to keep in touch with family and friends, but their lifestyle has changed little for centuries. The sound of cowbells and the bark of longhaired mastiffs starts early in the morning as the animals – often decorated with traditional woollen balls on their horns – are herded up steep, narrow paths. (Photo by Rafael Marchante/Reuters)

Men hang at the back of a truck loaded with farm produce along a road in Ikeja district in the commercial capital Lagos, Nigeria December 19, 2016. (Photo by Akintunde Akinleye/Reuters)

A light railway train passes through a residential building on March 18, 2017 in Chongqing, China. Chongqing Rail Transit No.2 and a 19-storey residential building have been built across each other. The railway set its Liziba Station on the sixth to eighth floor in the building with noise reduction equipment. (Photo by VCG/VCG via Getty Images)

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)

A 1949 Porsche 356 SL is displayed during the Porsche Rennsport Reunion V at Laguna Seca Raceway near Salinas, California, September 26, 2015. The three-day reunion is billed by organizers as the world's largest gathering of Porsche racecars, renowned drivers, and Porsche collector cars. (Photo by Michael Fiala/Reuters)

Tourists walk above a tea plantation in Enshi, Hubei province, December 27, 2015. (Photo by Reuters/Stringer)