Saintsetseg Jambaldorj, a member of the Tsaatan ethnic minority, one of the last remaining groups of nomadic reindeer herders in East Taiga, Mongolia, wearing a traditional deel, on July 5, 2016. (Photo by Madoka Ikegami/Barcroft Images)

The ruins of a castle stand above the town of Rocca Calascio, close to Santo Stefano di Sessanio in the province of L'Aquila in Abruzzo, inside the national park of the Gran Sasso e Monti della Laga, Italy, September 7, 2016. (Photo by Siegfried Modola/Reuters)

A student from “the cliff village” in Atule'er climbs newly-constructed steel ladders after school to go home for holidays, in Liangshan Sichuan province, China, November 19, 2016. The steel ladders which replaced the unsafe vine ladders shortened the time taken for the children to go home, from three hours to two. (Photo by Reuters/Stringer)

A woman tour skates on the frozen lake of Orlangen, south of Stockholm, Sweden, on December 23, 2016. Tour skating is recreational long distance ice skating on natural ice particularly popular in the Nordic countries. (Photo by Tobias Roestlund/AFP Photo/TT News Agency)

UConn students from Storrs, Conn., Gary Tu, Danny Wang and Victor Zheng, fish at Shenipsit Lake in Tolland, Conn. during sunset on Tuesday, August 19, 2014. (Photo by Jim Michaud/AP Photo/Journal Inquirer)

Australia's Richie “Vas” Vaculik maneuvers past another surfer ducking under the wave during the inaugural Red Bull Cape Fear invitational surfing tournament off the shores of southern Sydney, August 31, 2014. (Photo by Jason Reed/Reuters)

A sun bear is offered chocolate by a visitor in its enclosure at a zoo in Bandung on January 18, 2017. Animal rights activists on January 18 demanded the closure of an Indonesian zoo after skeletal sun bears were pictured begging for food from visitors and eating their own dung. (Photo by Timur Matahari/AFP Photo)

A mahout cleans the dust from his elephant in Ahmedabad, India, February 8, 2017. (Photo by Amit Dave/Reuters)