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)

Jude Hajjaj, carries her cat near a picture of her cat painted on the wall by her father Osama Hajjaj, who teams up with his neighbours in creating works of art at their roof during the curfew imposed by the Jordanian government amid concerns over the spread of the coronavirus disease (COVID-19) in Amman, Jordan, May 10, 2020. (Photo by Muhammad Hamed/Reuters)

A resident brings his dog that uses a mask in Jakarta, Indonesia, on May 12, 2020. (Photo by Jefta Images/Barcroft Media via Getty Images)

A man wearing a beard imprinted facemask as a preventive measure against the COVID-19 coronavirus walks along a street in New Delhi on June 19, 2020. India has recorded more than 380,000 cases of COVID-19, the fourth-highest in the world, with over 12,500 deaths, health ministry data show. (Photo by Jewel Samad/AFP Photo)

A boy attends Eid al-Adha prayers on the street outside Abu Hanifa mosque in Baghdad Adhamiya district, during the outbreak of the coronavirus disease (COVID-19), in Iraq, July 31, 2020. (Photo by Thaier Al-Sudani/Reuters)

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)

A Flame Skimmer or Firecracker Skimmer dragonfly (Libellula saturata) rests on a small branch in Topanga, California, USA, 18 June 2018. The Flame Skimmer dragonfly is found in the Western United States near ponds and creeks. (Photo by Mike Nelson/EPA/EFE)