Medic James E. Callahan of Pittsfield, Mass., gives mouth-to-mouth resuscitation to a dying soldier in war zone D, about 50 miles northeast of Saigon, June 17, 1967. Thirty-one men of the 1st Infantry Division were reported killed in the guerrilla ambush, with more than 100 wounded. (Photo by Henri Huet/AP Photo)

Members of the Oath Keepers and general public return fire during a simulated attack as they take part in a tactical training session in northern Idaho, U.S. October 1, 2016. In April 2015 Reuters photographer Jim Urquhart was assigned to cover the Oath Keepers during a tour of the Sugar Pine gold mine in Oregon after the group of former cops, military, firefighters and other first responders had risen to prominence during a standoff in Nevada over land rights. (Photo by Jim Urquhart/Reuters)

A picture made available 26 April 2016 shows a tiger playing in the water with a trainer nicknamed “Super Tiger Man” at the Tiger Temple in Kanchanaburi province, Thailand, 24 April 2016. The site known in Thai as “Wat Pa Luangta Maha Bua Yannasampanno” has been the focus of a dispute with the Department of National Parks, Wildlife and Plant Conservation (DNP) after the DNP asked in 2015 that the temple hands over its 147 tigers since it was not licensed to keep them. The temple has requested for a zoo license according to its managing director. (Photo by Diego Azubel/EPA)

Men carry a dog, wearing a costume and seated on a stool, as a form of respect as they believe that dogs found water for their ancestors, during a local festival for the Miao ethnic minority in Jianhe county, Guizhou Province, China, August 14, 2016. (Photo by Reuters/China Daily)

German troops in Stalingrad, USSR. September 10, 1942. (Photo by TASS)

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

Two Girls who managed to evade the police walk away as police on foot and horseback push back to te curd at Park Row, In New York on April 26, 1960, A milling throng of more than 1,000 High students who storned city hall in a Demonstration supporting teachers wage demands. (Photo by AP Photo)

A visitor looks at a Soviet-made «Zaporozhets» retro car, which was converted into an aquarium at a small and medium business exhibition in St. Petersburg, Russia on December 5, 2018. (Photo by Anton Vaganov/Reuters)