Gelada baboons (Theropithecus gelada) play in their enclosure at the Zoo in Zurich, Switzerland, Wednesday, May 15, 2013. (Photo by Steffen Schmidt/Keystone/AP Photo)

Volunteers try to keep alive some of the hundreds of stranded pilot whales after one of the country's largest recorded mass whale strandings, in Golden Bay, at the top of New Zealand's south island, February 10, 2017. Volunteers in New Zealand managed to refloat about 100 surviving pilot whales on Saturday, February 11, 2017 and are hoping they will swim back out to sea after more than 400 of the creatures swam aground at a remote beach. (Photo by Ross Wearing/Reuters)

Demi Rose attends Sixty6 Magazine – issue two launch party at Paper club on March 22, 2017 in London, England. (Photo by Splash News and Pictures)

Myanmar's military parade to mark the 72nd Armed Forces Day in the capital Naypyitaw, Myanmar March 27, 2017. (Photo by Soe Zeya Tun/Reuters)

Demonstrators clash with members of the Bolivarian National Police as protests continue in Caracas, Venezuela, 20 April 2017. The Bolivarian National Guard, using tear gas, tried to disperse protests against the government of Venezuelan President Nicolas Maduro. (Photo by Miguel Gutierrez/EPA)

This picture taken on October 20, 2016 shows students practising wushu at the Tagou martial arts school in Dengfeng. China is investing hugely in football training and has vowed to have 50 million school- age players by 2020, as the ruling Communist party eyes “football superpower” status by 2050. (Photo by Nicolas Asfouri/AFP Photo)

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)

Hugh Hefner spanks playboy models Izabella Kasprzyk and Bridget Marquardt during their birthday dinner party at Joya restaurant on September 25, 2002 in Beverly Hills, California. Playboy founder and sеxual revolution symbol Hugh Hefner has died at age 91. The magazine released a statement saying Hefner died at his home in Los Angeles of natural causes on Wednesday night, September 27, 2017, surrounded by family. (Photo by David Klein/Getty Images)