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

German Nazi leader Adolf Hitler (1889 - 1945) enjoys a quiet picnic between meetings, circa 1933. Picture 196 of a series of collectable images published in Germany during the Nazi period, entitled “Deutschland Erwacht” (Germany Awakes). (Photo by Heinrich Hoffmann/Hulton Archive/Getty Images)

An air raid drill at Seattle College caught students William Bates, left, and Edna Mae Farrell, right, while they were eating their lunch in the school café, but they simply took shelter under the table and continued eating in Seattle, Washington, March 17, 1942. Air raid wardens said 350 students left their classrooms and assembled in shelters within one minute in first at the college. (Photo by AP Photo)

Models present creations by Georgian designer Lasha Jokhadze during the Tbilisi Fashion Week in Tbilisi, Georgia, October 19, 2018. (Photo by David Mdzinarishvili/Reuters)

A soldier eats ice cream as she visits a zoo in Pyongyang, North Korea, September 12, 2018. (Photo by Danish Siddiqui/Reuters)

A mural painted on a fence depicts US President Donald Trump as the Coronavirus in San Francisco, California on April, 01, 2020. All 40 million residents of California were Thursday ordered to stay at home indefinitely in a bid to battle the coronavirus pandemic in the nation's most populous state. (Photo by Josh Edelson/AFP Photo)

A train attendant wearing a protective face mask stands on a train to Wuhan, at the railway station in Beijing, China, 29 March 2020. Wuhan, the epicenter of the coronavirus outbreak, partly lifted the lockdown allowing people to enter the city after more than two months. Chinese authorities eased the quarantine measures as cases of Covid-19 across China have plummeted, according to Chinese government figures. (Photo by Roman Pilipey/EPA/EFE)

Thai dancers use face shield while waiting for worshippers, after the government eased some coronavirus restrictions, at the Erawan shrine, a popular tourists site, in Bangkok, Thailand, 03 May 2020. The Thai government announced that some businesses and shops can reopen and services and some activities can be resumed from 03 May 2020 on as long as social distancing and regulations are in place. (Photo by Narong Sangnak/EPA/EFE/Rex Features/Shutterstock)