A competitor walks on tightrope during a performance in Taizhou, Zhejiang Province, China, May 7, 2016. (Photo by Reuters/China Daily)

Armed man stand at entrance of the naval headquarters in Sevastopol, March 19, 2014. Around a dozen Ukrainian servicemen, unarmed and in civilian clothes, walked out of the Ukrainian naval headquarters in the Crimean port of Sevastopol on Wednesday after it was taken over by pro-Russian forces, a Reuters witness said. (Photo by Baz Ratner/Reuters)

German shoemaker Georg Wessels (R) presents shoes to Win Zaw Oo, who according to his medical team, at 2.3 metres (7.5 ft), is Myanmar's tallest man, in Yangon March 26, 2014. (Photo by Reuters/Minzayar)

“Just hanging out”. As full autumn hits the valley of Hallingdal in Norway, this bear chills out in a tree which seems to barely cover its weight. Photo location: Flå, Hallingdal, Norway. (Photo and caption by Jorgen Tharaldsen/National Geographic Photo Contest)

Kirby Chambliss of the United States flies in formation with Matt Hall of Australia, Yoshihide Muroya of Japan and Nigel Lamb of Britain prior to the third stage of the Red Bull Air Race World Championship in front of the Petronas Towers in Kuala Lumpur, Malaysia, on May 15, 2014. (Photo by Joerg Mitter/Red Bull via Reuters)

Large trumpet vines spread across electrical lines next to a highway in Kinston, N.C., on June 23, 2014. (Photo by Janet S. Carter/Kinston Free Press via AP Photo)

British rally driver Kris Meeke jumps his Citroen over a brow during the fifth special stage of the World Rally Championship (WRC) Rally of Australia, near Bellingen on the New South Wales central coast on September 12, 2014. (Photo by William West/AFP Photo)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)