Sarah Bui poses for photographer, Brian Le around blossoming cherry trees, near the Tidal Basin on Thursday March 23, 2017 in Washington, DC. (Photo by Matt McClain/The Washington Post)

Sjinkie Knegt of Netherlands, left, and Park Se-Yeong of South Korea crash out as they compete in a men's 1500m short track speedskating final at the Iceberg Skating Palace during the 2014 Winter Olympics, Monday, February 10, 2014, in Sochi, Russia. (Photo by Bernat Armangue/AP Photo)

A monkey is led by its trainer Qi Defang during training for a circus in Suzhou, Anhui province, November 29, 2014. Suzhou is known as the hometown of circus troupes in China and has more than 300 circus troupes. (Photo by William Hong/Reuters)

A Venezuelan Bolivarian National Police officer fires tear gas towards demonstrators during a protest in Caracas, Venezuela, Monday, April 10, 2017. Thousands of people in Venezuela's capital are protesting against the government of President Nicolas Maduro, demanding new elections and vowing to stay in the streets during the usually quiet Easter Week. (Photo by Fernando Llano/AP Photo)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)

Protesters sit in a cafe during a “SlutWalk” protest, in which several hundred participants march through the centre of Jerusalem, May 13, 2016. The SlutWalk movement began after a Toronto policeman suggested in 2011 that women could avoid sexual assault by not dressing like a “sl*t”. (Photo by Amir Cohen/Reuters)