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)

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)

Public Space series, 2015. This series by Morteza Niknahad and Behnam Zakeri tends toward cinema, taking an almost cartoonish view of modern life in Iran. This work was inspired by the social life of dolphins. (Photo by Morteza Niknahad and Behnam Zakeri/The Guardian)

A cyclist drives past a flowering rapeseed field not far from the small Bavarian village of Schoengeising, near Munich, during a nice, warm sunny weather day on May 17, 2017. (Photo by Christof Stache/AFP Photo)

A surfer takes some air off a wave while surfing after sunset in Cardiff, California, U.S., January 7, 2020. (Photo by Mike Blake/Reuters)

An aircraft crosses a bridge over a highway the airport in Frankfurt, Germany, Friday, September 20, 2019. Protests of the “Friday For Futurte” movement against the increase of carbon dioxide emissions are planned Friday in cities around the globe. In the United States more than 800 events were planned Friday, while in Germany more than 400 rallies are expected. (Photo by Michael Probst/AP Photo)

A handout photo provided by the Police department in Lippe on 01 June 2015 of a British “Challenger 2” tank after it rolled over a car's front in Lippe, Germany, 01 June 2015. Police reported that a 18-year old female driving beginner from Detmold apparently overlooked a convoy of tanks when she turned left onto the Panzeringstrasse (lit. Tank Ring Road). (Photo by EPA/Polizei Lippe)

The moon rising above the Forth Rail Bridge in The Firth of Forth from North Queensferry, England on July 16, 2019. (Photo by South West News Service)