Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)

A picture made available on 30 March 2016 shows members of the anti-terror squad of the local paramilitary force have a training in Suining, in southwest Sichuan province, China, 29 March 2016. (Photo by Zhong Min/EPA)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Christian people crowd a bush taxi on a road 55km north of Bangui as they are on their way to the capital where they expect to sell some products on the market on January 19, 2014. Fresh fighting broke out in the strife-torn Central African Republic on the eve of an announcement on Sunday of the candidates seeking to become the new interim president. Sectarian violence has gripped the landlocked country after a March 2013 coup launched by the mostly Muslim Seleka rebels, and the UN has warned that the bloodshed could turn into genocide. (Photo by Eric Feferberg/AFP Photo)

Members of Chinese Shaolin Temple Warrior Monks perform martial arts during the “Cultures of China, Festival of Spring” Gala in Toronto, Canada, on February 27, 2016. (Photo by Zou Zheng/Xinhua/Sipa USA)

A woman eats candy in the shape of a phallus during the Kanamara Matsuri, or Iron Phallus Festival through a street near the Kanamara shrine in Kawasaki outside of Tokyo April 5, 2015. The festival celebrates fertility and is used to raise awareness and money for the prevention of sexually transmitted diseases. (Photo by Thomas Peter/Reuters)

An exile Tibetan monk gestures as he makes a point in a dialectics debate with another monk, sitting right, at the Kirti monastery in Dharmsala, India, Monday, January 18, 2016. The debate is an essential part of their training as Buddhist monks. (Photo by Ashwini Bhatia/AP Photo)

A woman holds an elderly woman on her back to cross a flooded street after a heavy rain in Shenyang, Liaoning province on July 14, 2017. (Photo by Fred Dufour/AFP Photo)