A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

Two holy men with a decorative faces and headdresses, taken in Kathmandu, Nepal. Wandering through the cities and forests of Nepal are the holy men, or Sadhus, who have left all materialistic pleasures behind to live a life devoted to God. Their appearances vary from brightly coloured face paints, and decorations, to minimalistic practical clothing, but they all represent the fundamental values and meanings of Hinduism. Danish photographer Jan Moeller Hansen visited the ancient capital city of Kathmandu between 2013 and 2016 and documented the mysterious holy wanderers. (Photo by Jan Moeller Hansen/Barcroft Images)

A woman sandboards on the mountain in Wadi el-Rayan Fayoum, Egypt, November 18, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

People climb on an artificial ice-wall in Liberec, about 100 km north of Prague, Czech Republic, Saturday, January 23, 2015. The wall was prepared in a former quarry just near the centre of the city. (Photo by Radek Petrasek/CTK via AP Photo)

Men work on a large hookah at the Taha factory in Baghdad, Iraq July 2, 2016. (Photo by Khalid al Mousily/Reuters)

Saudi children of al-Fefi family walk up the stairs as they make their way to their schools through Fifa Mountain, in Jazan, south of Saudi Arabia, December 15, 2016. (Photo by Mohamed Al Hwaity/Reuters)

A girl looks with comic disgust at a guy who falls asleep with a bottle of beer at a party; her friend laughs. (Photo by Edward Corbett/Rex Features/Shutterstock)

An artist draws a tattoo on a woman's arm during a tattoo convention in Ljubljana April 18, 2015. (Photo by Srdjan Zivulovic/Reuters)