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)

People participate in the first day of Thingyan Water Festival in Naypyitaw, Myanmar on April 13, 2018. The annual water festival, known as Thingyan, features large groups of people congregating to celebrate the by splashing water and throwing powder at each other's faces as a symbol of cleansing and washing away the sins from the old year. It marks the start of the traditional New Year and is similarly celebrated in countries such as Myanmar, Thailand, Laos and Cambodia. (Photo by Hein Htet/EPA/EFE/Rex Features/Shutterstock)

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

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 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)

Model Bella Hadid walks the runway for the Savage X Fenty Fall/Winter 2018 fashion show during NYFW at the Brooklyn Navy Yard on September 12, 2018 in Brooklyn, NY. (Photo by Kevin Mazur/Getty Images for Savage X Fenty)

Bollywood actress and former p*rn star Sunny Leone stands with her wax likeness during its unveiling at the Madame Tussauds museum in New Delhi, India, Tuesday, September 18, 2018. The statue unveiled Tuesday represents the 37-year-old celebrity's acceptance by mainstream Indian society even as conservative Indian politicians condemn her p*rn-star past. (Photo by Anupam Nath/AP Photo)

U.S. first lady Melania Trump steps out of her motorcade vehicle as she departs Washington for a tour of several African countries from Joint Base Andrews, Maryland, U.S., October 1, 2018. (Photo by Carlo Allegri/Reuters)