A Lion-Tailed macaque holds a big block of ice with a mix of frozen vegetables and fruit at the zoo in Leipzig, central Germany, Friday, July 19, 2013. Weather forecasts predict sunny weather and warm temperatures for Germany in the next few days. (Photo by Jens Meyer/AP Photo)

Sumatran tiger Jumilah is seen with one of her cubs on display at Taronga Zoo on October 25, 2011 in Sydney, Australia. The Sumatran tiger cubs, born in August to mother Jumilah, will meet the public for the first time this week. (Photo by Mark Kolbe/Getty Images)

In the spring of 1965, within weeks of 3,500 American Marines arriving in Vietnam, a 39-year-old Briton named Larry Burrows began work on a feature for LIFE magazine, chronicling the day-to-day experience of U.S. troops on the ground – and in the air – in the midst of the rapidly widening war. The photographs in this gallery focus on a calamitous March 31, 1965, helicopter mission; Burrows’ “report from Da Nang”, featuring his pictures and his personal account of the harrowing operation, was published two weeks later as a now-famous cover story in the April 16, 1965, issue of LIFE.

Photo: Man your battle stations: The crew chief of helicopter Yankee Papa 13, lance corporal James C. Farley, mans an M-60 machine gun during a mission near Da Nang, Vietnam on March 31, 1965. (Photo by Larry Burrows/Time & Life Pictures)

Maasai men of Matapato jostle to parade as they attend the Olng'esherr (meat-eating) passage ceremony to unite two age-sets; the older Ilpaamu and the younger Ilaitete into senior elderhood as the final rite of passage, in Maparasha hills of Kajiado, Kenya on September 23, 2020. Thousands of Maasai men clad in red and purple shawls and with their heads coated in red ochre gathered this week for a ceremony that transforms them from Moran (warriors) to Mzee (elders). (Photo by Thomas Mukoya/Reuters)

Mahmoud El Komy, a 26-year-old Egyptian mechatronics engineer, stands beside Cira 3, a remote-controlled robot that runs tests on suspected coronavirus disease (COVID-19) patients, to limit the human exposure to the virus, amid a second wave of infections in Tanta, Egypt, November 18, 2020. (Photo by Mohamed Abd El Ghany/Reuters)

People wearing face masks walk through Ginza area on December 27, 2020 in Tokyo, Japan. Japan announced it will close its borders to non-resident foreign nationals from tomorrow until the end of January after two people were discovered to be infected with a new strain of Covid-19 coronavirus that has begun spreading around the world. The country is also grappling with a surge in coronavirus infections, with Tokyo reporting 708 cases today. To date, Japan has recorded 218,453 infections, 3,052 deaths and 3,052 recoveries from the virus. (Photo by Yuichi Yamazaki/Getty Images)

A woman takes part in a demonstration against police violence during the recent rallies of opposition supporters following the presidential election in Minsk, Belarus on August 12, 2020. (Photo by Vasily Fedosenko/Reuters)