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)

Children, wearing red neckerchiefs, a symbol of the Pioneer Organization, salute during a ceremony for the inauguration of 18 new members at a local school in the southern settlement of Kazminskoye in Stavropol region, Russia, November 19, 2015. Early pro-communist youth movements, which appeared in Russia after the 1917 Bolshevik revolution, were reformed into the Pioneer Organization of the Soviet Union. While the organization lost its dominance among students in post-Soviet Russia, some educational institutions and families still carry on this tradition. (Photo by Eduard Korniyenko/Reuters)

Palestinian girl Manar Al-Shinbari (R), 15, who lost her both legs by what medics said was Israeli shelling at a UN-run school where she was taking refuge during the 50-day war last summer, is helped by her sister to put on her headscarf in an apartment in Jabaliya refugee camp in the northern Gaza Strip January 13, 2015. Manar's mother and three of her brothers were killed in the same incident. The girl's family house was destroyed by Israeli shelling during the war. (Photo by Mohammed Salem/Reuters)

South Korean traditional bow artisan Kwon Yeong-Hak works on a bow in his workshop in Yecheon-gun, Gyeongsangbuk-do, South Korea, 26 February 2015. Kwon Yeong-Hak still crafts his bows in the traditional way, carrying on a four-generation family business. The Gakgung bow, of which Kwon is one of the last remaining artisans, is unique to Korea, and is constructed with a variety of materials, including water buffalo horn, oak, bamboo and cattle spinal sinew. A ban on the import of water buffalo horns has put the Gakgung tradition at risk. (Photo by Jeon Heon-Kyun/EPA)

In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)

Evan Leversage, who is terminally ill with brain cancer, is greeted by a Christmas decorated dog with his mother Nicole Wellwood (L), and his father Travis Leversage (2nd R) in St. George, Ontario, Canada October 24, 2015. Evan Leversage is a seven-year-old boy who has been living with inoperable brain cancer since he was two years old. His family has organized a Christmas celebration in October complete with a full parade, in case Evan does not live to celebrate his last Christmas day on the traditional date of December 25, according to local media. (Photo by Mark Blinch/Reuters)

Devotees offer prayers before taking a holy bath during the Swasthani Bratakatha festival in the Triveni River in Panauti near Kathmandu January 24, 2015. During the month long festival, devotees recite one chapter of a Hindu tale daily from the 31-chapter sacred Swasthani Brata Katha book that is dedicated to the God Madhavnarayan and the Goddess Swasthani, alongside various other gods and goddess and the miraculous feats performed by them. The devotees also go on pilgrimages to various temples, perform religious rituals, take a holy bath in the rivers and fast for a month, especially among women who believe fasting helps in their family's well-being or in getting them a good husband. (Photo by Navesh Chitrakar/Reuters)

Devotees offer prayer by rolling on the street during the final day of the month-long Swasthani festival of Bhaktapur, near Kathmandu, February 3, 2015. During the festival, devotees recite one chapter of a Hindu tale daily from the 31-chapter sacred Swasthani Brata Katha book, that is dedicated to God Madhavnarayan and Goddess Swasthani, alongside various other gods and goddesses and the miraculous feats performed by them. The devotees also go on pilgrimages to various temples, perform religious rituals, take a holy bath in the rivers and fast for a month, especially among women who believe fasting helps in their family's well-being or in getting them a good husband. (Photo by Navesh Chitrakar/Reuters)