In this June 20, 2015 photo, Niberta Galvez uses the bottom half of his shirt to collect coca leaves in Samugari, Peru. Coca farmers were among the locals who, in 1984, formed citizen militias to help the military beat back Shining Path rebels, reducing them to a small group of fewer than 500 who now are deeply involved in drug trafficking. (Photo by Rodrigo Abd/AP Photo)

Goat herder Dana McGregor's goats Pismo, left, and Goatee surf at San Onofre State Beach, Calif, on July 11, 2012. McGregor started taking Pismo's mother Goatee to the beach, and it wasn't long before she was on a surfboard. When Pismo was born, McGregor put her on a board too, and she was a natural, he says. (Photo by Rod Veal/The Orange County Register via AP)

Caroline Wozniacki of Denmark serves in her match against Kaia Kanepi of Estonia during day four of the Toray Pan Pacific Open at Ariake Colosseum on September 28, 2011 in Tokyo, Japan. (Photo by Koji Watanabe/Getty Images)

Masked Guggen music bands parade through the streets on the occasion of the beginning of the Fasnacht Carnival of Lucerne, Switzerland, early 23 February 2017. (Photo by Urs Flueeler/EPA)

A boy jumps into a pool of mud during the traditional “Bloco da Lama” or “Mud Street” carnival party, in Paraty, Brazil, Saturday, February 25, 2017. Legend has it the “bloco” was born in 1986 after local teens hiking in a nearby mangrove forest smeared themselves with mud to discourage mosquitoes and then wandered through Paraty. The party grew year after year, but revelers eventually were banned from parading in the colonial downtown after shopkeepers complained pristine white walls were stained with the hard-to-remove mud. (Photo by Mauro Pimentel/AP Photo)

A boy dressed as Hindu Lord Shiva poses before performing in a religious procession at the Mahashivratri festival in Allahabad, India, March 7, 2016. Hindus across the country celebrate Mahashivratri, better known as Lord Shiva's wedding anniversary. (Photo by Jitendra Prakash/Reuters)

Wild elephants, including a tusker (C), rummage through garbage dumped at an open ground in the village of Digampathana in north- central Sri Lanka on August 19, 2017. Sri Lanka has banned the dumping of garbage at open fields and near wildlife reserves, but the practice continues. (Photo by Lakruwan Wanniarachchi/AFP Photo)

This photo taken on October 8, 2017 shows dancers posing in formation to celebrate the upcoming Party Congress, in Rongan in China' s southern Guangxi region. China will convene its 19 th Party Congress on October 18, state media said, a key meeting held every five years where President Xi Jinping is expected to receive a second term as the ruling Communist Party' s top leader. (Photo by AFP Photo/Stringer)