A cultural dance group waits to perform at Gambela stadium during Ethiopia's Nations and Nationalities Festival in Gambela town, in Ethiopia December 8, 2015. Picture taken December 8, 2015. (Photo by Tiksa Negeri/Reuters)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

Nepalese students of Himalayan agriculture college play in mud water in a paddy field to celebrate the National Paddy Day in Badegaun village, Lalitpur, Nepal, 29 June 2016. More than 100 students and teachers of Himalayan agriculture college participated in the National paddy day by planting rice and playing in mud water as Nepal is celebrating National Paddy Day with various event. (Photo by Narendra Shrestha/EPA)

Irene Aguirre, 23, attends a boxing class at the National Institute of Sport in Managua March 4, 2015. A study done by the Psychology alumni of the National Autonomous University of Nicaragua (UNAN-Managua) revealed that about 1 million women in Nicaragua suffer from domestic violence. (Photo by Oswaldo Rivas/Reuters)

Nicaraguan army members carry a participant playing the role of a victim during a national multi-hazard drill organized by the National System for Prevention, Mitigation and Attention to Disasters (SINAPRED), in the 30 de Mayo neighborhood in Managua, Nicaragua, September 26, 2016. (Photo by Oswaldo Rivas/Reuters)

From the “Paradise Revisited” story in the November 2013 issue of National Geographic magazine, this image is a beautiful vision of father and son fishermen as they move through the multicolored coral gardens of Kembe Bay, Papua New Guinea, in a traditional outrigger canoe. (Photo by David Doubilet/National Geographic Creative)

Demonstrators clash with members of the Bolivarian National Police as protests continue in Caracas, Venezuela, 20 April 2017. The Bolivarian National Guard, using tear gas, tried to disperse protests against the government of Venezuelan President Nicolas Maduro. (Photo by Miguel Gutierrez/EPA)

Dancers of the Czech National Ballet warm up backstage during a performance of “The Nutcracker – A Christmas Carol” at the National Theatre in Prague, Czech Republic, late 16 December 2017. Peter I. Tchaikovsky's “The Nutcracker”, one of his most famous compositions and seasonal ballets, premiered in St. Petersburg, Russia, on 18 December 1872, celebrates its 125th anniversary this year. (Photo by Martin Divisek/EPA/EFE)