Belarusian people take part in the Ivan Kupala festival near the town of Rakov, west of Minsk June 27, 2015. The ancient tradition, originating from pagan times, is usually marked with grand overnight festivities. On Kupala night, people sing and dance around campfires, believing it will purge them of their sins and make them healthier. (Photo by Vasily Fedosenko/Reuters)

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)

A Naga sadhu, or naked Hindu holy man, pauses inside a tent during Kumbh Mela, or Pitcher festival, at Trimbakeshwar, India, Thursday, August 27, 2015. Hindus believe taking a dip in the waters of a holy river during the festival will cleanse them of their sins. The festival is held four times every 12 years. (Photo by Bernat Armangue/AP Photo)

A man walks with a giant rake during carnival celebrations in Zubieta January 27, 2015. Bell carrying dancers known as Joaldunak from Zubieta and neighbouring Ituren visit each other's villages performing a ritual dance to ward off evil spirits and awaken the coming spring. Alongside the dancers, villagers dress in bizarre and frightening costumes to harass and scare visitors. (Photo by Vincent West/Reuters)

A park ranger stands next to a nothern white female rhinoceros named Najin at Ol Pejeta Conservancy, some 290 kms north of the Kenyan capital, Nairobi, on January 27, 2015. Najin is one of only five members of the sub-species left on the planet, three of which reside at Ol Pejeta Conservancy. Conservationists and scientists met in Kenya this week to come up with a last ditch plan to save the northern white rhinoceros from extinction. (Photo by Tony Karumba/AFP Photo)

In this Friday, February 27, 2015 photo, an Israeli high-school senior preparing to join the Israeli military later this year participates in a privately run training camp for military combat fitness near Yakum, central Israel. With a mandatory three-year military service looming after graduation, teenage boys, and increasingly girls too, are gearing up for the draft, getting into shape and trying to improve their chances of acceptance into elite combat units. (Photo by Oded Balilty/AP Photo)

Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 “Occupy Central” civil disobedience movement in Hong Kong September 27, 2014. Hong Kong riot police used pepper spray on Saturday to disperse dozens of students who had stormed government headquarters, but an equal number held their ground in protests against Beijing's tightening grip on the city. (Photo by Tyrone Siu/Reuters)

Riot police arrest an anti-government protester in Ouagadougou, capital of Burkina Faso, October 30, 2014. Thousands of protesters marched on Burkina Faso's presidential palace after burning the parliament building and ransacking state television offices on Thursday, forcing President Blaise Compaore to scrap a plan to extend his 27-year rule. Emergency services said at least three protesters were shot dead and several others wounded by security forces when the crowd tried to storm the home of Compaore's brother. Security forces also fired live rounds and tear gas at protesters near the presidency in the Ouaga 2000 neighborhood. (Photo by Joe Penney/Reuters)