A family take a souvenir picture next to giant male panda Xiao Liwu, who was born at the San Diego Zoo and will be repatriated to China with his mother Bai Yun, bringing an end to a 23-year-long panda research program in San Diego, California, U.S., April 18, 2019. (Photo by Mike Blake/Reuters)

In this photo taken on Sunday, March 10, 2019, a little girl laughs during a ritual marking the upcoming Clean Monday, the beginning of the Great Lent, 40 days ahead of Orthodox Easter, on the hills surrounding the village of Poplaca, in central Romania's Transylvania region. Romanian villagers burn piles of used tires then spin them in the Transylvanian hills in a ritual they believe will ward off evil spirits as they begin a period of 40 days of abstention, when Orthodox Christians cut out meat, fish, eggs, and dairy. (Photo by Vadim Ghirda/AP Photo)

A dachshunds is dressed in an outfit as it is shown off during the eighth annual Dachshunds Parade in Saint Petersburg, Russia on May 25, 2019. (Photo by Olga Maltseva/AFP Photo)

Ammunition airlift into besieged Khe Sanh, Operation Pegasus, April 1968. (Photo by Larry Burrows/AP Photo)

People dressed as a dancing devils with giant mask dance on a street, during a traditional celebration in Naiguata, Venezuela, Thursday, May 31, 2018. Carrying in their hands striking masks mostly animals and sea monsters, hundreds of men, women and children went out to dance frantically as possessed by evil spirits in an ancient ritual known as Dancing Devils of Naiguata, the unorthodox way of the coastal towns of Venezuela to venerate God during the celebrations of Corpus Christi. (Photo by Ariana Cubillos/AP Photo)

Senior Buddhist monk Lobsang Tayang sits outside the Amarbayasgalant Monastery in the Baruunburen district, Selenge province, Mongolia, April 26, 2018. (Photo by Thomas Peter/Reuters)

Alexandra Mazo, 12, with her cellphone on her way down the mountain after finishing school. The remote mountain village of Pueblo Nuevo has been highly affected by the armed conflict and direct combat between the national army and Farc guerrillas due to its strategic location and the intensive production on coca crops on the surrounding hillsides. (Photo by Mads Nissen/Politiken/The Guardian/Panos Pictures/The Nobel Peace Center)

A woman from the Hui Muslim community carries food that will be eaten by her and others to break their fast during the holy fasting month of Ramadan at the Nanxiapo Mosque on June 8, 2018 in Beijing, China. (Photo by Kevin Frayer/Getty Images)