In this photo taken on July 19, 2014, a man looks at an excavation as an A.R.M.H., Association for the Recovery of Historical Memory, volunteer digs on the search for the body of Perfecto de Dios, in a hidden grave in Chaherrero, Spain. Across Spain, volunteer teams of archeologists, anthropologists and forensic scientists head out every year on expeditions to dig for suspected mass graves – a legacy of Spain's fascist past during the time of General Francisco Franco. (Photo by Daniel Ochoa de Olza/AP Photo)

In this photo submitted by the Washington Post tilted “The Moment Time Stopped”, survivors piled bodies of the dead outside for weeks after earthquake on January 14, 2010 in Port-au-Prince, Haiti. The 7.0 magnitude earthquake struck in 2010, and the Haitian government has said more than 300,000 people were killed. The exact toll is unknown because there was no systematic effort to count bodies among the chaos and destruction. (Photo by Carol Guzy/AP Photo/The Washington Post)

In this February 2, 2015 photo, tourists jump as they pose for a picture, after disembarking from the Ocean Nova cruise ship, on King George Island, Antarctica. This tourist season, which runs November through March, more than 37,000 visitors are expected to walk on the coldest continent on Earth, about 10 percent more than the year before. (Photo by Natacha Pisarenko/AP Photo)

March 28, 1967. Egg Roll; A large bunny attracted the attention of children and their parents during the annual Easter egg roll Monday on the south lawn of the White House. The bunny was made by Fred Johansen, Silver Spring, Md. Nearly 17,000 youngsters and adults took part in the egg rolling. The President and Mrs. John-son were not at the festivities because they were in Camp David, Md. The tradition of egg rolling was begun in 1878 during the administration of Rutherford B. Hayes. (Photo by Minneapolis Star Tribune)

Police officers display their AI-powered smart glasses in Luoyang, Henan province, China on April 4, 2018. (Photo by Reuters/China Stringer Network)

Blossoms and dust are blown by the wind as Jasmin Ricks, left, and her sister, Jessica Ricks, center, take in the cherry blossoms near the Tidal Basin in Washington on April 12, 2018. (Photo by Matt McClain/The Washington Post)

A woman walks past servicemen of the self-proclaimed Donetsk People's Republic (DNR), who take part in a rehearsal for the Victory Day parade in Donetsk, Ukraine on May 3, 2018. (Photo by Alexander Ermochenko/Reuters)

A cosplayer poses for a photograph during the Tokyo Rainbow Pride Parade on May 6, 2018 in Tokyo, Japan. The LGBT community and supporters marched down Shibuya and Harajuku areas on the final day of the Tokyo Rainbow Pride 2018 event. (Photo by Tomohiro Ohsumi/Getty Images)