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)

A couple takes a selfie as Hoa Binh hydroelectric power plant opens the flood gates after a heavy rainfall caused by Talas typhoon in Hoa Binh province, outside Hanoi, Vietnam July 20, 2017. (Photo by Reuters/Kham)

Storm erupts over Pacific Ocean as plane zooms past at 37,000 ft. The amazing picture shows a massive cloud erupting against a starry night sky as the off-duty airman Santiago Borja flew over the Pacific near Panama City. He had just moments to take the breathtaking snap as the Boeing 767 zoomed by at 37,000 ft on its way from North America to Ecuador. He also had take the picture perfectly in time with the flash of lightning to capture the storm in all its glory. (Photo by Santiago Borja/Solent News)

This handout picture taken on December 13, 2016 and released on December 14, 2016 by the Tiergarten Schoenbrunn zoo in Vienna, Austria, shows a baby sloth eating some salad as it hangs on it's mother's belly in their enclosure. The baby was born already on November 18, 2016, but according to the zoo it could be picured for the first time only now as it usually hides in it's mother's soft coat. (Photo by Daniel Zupanc/AFP Photo)

Pals let their hair down for one last hoorah in Cardiff, capital of Wales on September 12, 2020. Groups of friends crammed into pubs and restaurants to “go out in style” before the “rule of six” is enforced on Monday. (Photo by Huw Evans Picture Agency/The Sun)

Kashmiri women walk in a garden covered with fallen Chinar leaves on the outskirts of Srinagar, Indian controlled Kashmir, Wednesday, November 4, 2020. Kashmiris collect fallen leaves in autumn to make charcoal for use during winters. (Photo by Dar Yasin/AP Photo)

Shortlist, open competition, lifestyle. Healing Vibes – the hot springs of Bagno Vignoni in Italy flow out at a temperature of about 49°C. They were appreciated by the Romans for their healing powers, and have been used as therapeutic treatments since the 12th century, under Emperor Federico II. (Photo by Stefano Butturini/Sony World Photography Awards)

This photograph taken during a government organised media tour shows people in traditional costume standing in Potala Palace Square as the Potala Palace – classified as a World Heritage Site by Unesco in 1994 – is seen in the background in the regional capital Lhasa, in China's Tibet Autonomous Region, on June 1, 2021. (Photo by Hector Retamal/AFP Photo)