An elephant sprays tourists with water in celebration of the Songkran Water Festival in Ayutthaya province, north of Bangkok, Thailand April 11, 2017. Trained elephants sprayed motorists and passers-by with water in Thailand's old capital city of Ayutthaya on Tuesday to welcome in the Buddhist New Year, known as “Songkran”. (Photo by Chaiwat Subprasom/Reuters)

A Pakistani labourer carries bricks on his back at a construction site at a residential area in Islamabad on March 29, 2017. (Photo by Aamir Qureshi/AFP Photo)

A glass skywalk in Wanyuan, Sichuan province, built along the side of a cliff, is the highest such skywalk anywhere in China on January 31, 2017. Some visitors have been proven to be terrified by the experience had to brace against the wall in fear. (Photo by Chinanew.com/AsiaWire)

Animal rights activists covered with fake blood sit on the floor during a protest against the use of animals in research to mark World Day for Animals in Laboratories in central Madrid April 24, 2014. The sign reads, “How many rabbits do your shampoo kill?”. (Photo by Andrea Comas/Reuters)

Jewish children in fancy dress during the annual Jewish holiday of Purim on March 12, 2017 in London, England. Purim is celebrated by Jewish communities around the world with parades and costume parties. Purim commemorates the defeat of Haman, the advisor to the Persian king, and his plot to massacre the Jewish people, 2,500 years ago, as recorded in the biblical book of Esther. (Photo by Dan Kitwood/Getty Images)

A girl jumps over a campfire while celebrating Ivan Kupala Night, a traditional Slavic holiday not far from Kiev on July 6, 2013. During the celebration, originating in pagan times, people plait wreaths, jump over fires, and swim naked. (Photo by Sergei Supinsky/AFP Photo)

Timbuktu: A UN peacekeeper from Burkina Faso stands guard at the Djinguereber mosque, built in the 14th century, during a visit by a UN delegation on election day in Timbuktu, Mali, July 28, 2013. (Photo by Joe Penney/Reuters)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)