France's Simon Billy gets ready to practice speed skiing on the Chabriere ski slope in Vars, on March 29, 2017. (Photo by Jean-Pierre Clatot/AFP Photo)

“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)

Kendall Jenner and Kylie Jenner seen in this celebrity social media picture on September 1, 2016. (Photo by XposurePhotos.com)

Animal rights activists, including musician Kris Reichert, center, hold up signs with writing in Italian reading; “Leather: a lethal look” and “I wouldn't wear animal skin even if I were dead” as they stage a demonstration in front of Milan's Duomo gothic cathedral, Italy, Wednesday, September 20, 2017. Milan Fashion Week previews kick off Wednesday with Gucci, leading up to the awards on Sunday night. (Photo by Luca Bruno/AP Photo)

Model Kendall Jenner attends the “120 Battements Par Minutes (120 Beats Per Minute)” screening during the 70th annual Cannes Film Festival at Palais des Festivals on May 20, 2017 in Cannes, France. (Photo by Eric Gaillard/Reuters)

Mahouts return home with their elephants carrying grass to feed them on the eve of the rhino census in Kaziranga National Park in Assam state, India, 24 March 2015. Kaziranga will be closed to visitors for the next two days for a census of the rhinos commencing 25 March, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)