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)

A lion rests in the Nairobi National Park, Kenya on January 6, 2021. (Photo by Tiksa Negeri/Reuters)

France's Orlann Ombissa-Dzangue and Czech Republic's Marcela Pirkova compete during a women's 60m heat at the 2021 European Athletics Indoor Championships in Torun on March 7, 2021. (Photo by Sergei Gapon/AFP Photo/Profimedia)

Heavy monsoon rains cause floods in several parts of Kolkata, West Bengal, India on June 17, 2021. (Photo by Sumit Sanyal/Anadolu Agency via Getty Images)

An aerial view taken on March 8, 2021, shows Chinese fishing vessel Lurong Yuan Yu that ran aground on reefs of Pointe-aux-Sables in Port Louis, Mauritius, on March 7, 2021. (Photo by L'Express Maurice/AFP Photo)

Gina Di Meo, journalist from ANSA sits during a media preview of Summit at One Vanderbilt in New York, October 1, 2021. The Summit viewing deck is spread across the top four floors on One Vanderbilt in Manhattan, the fourth tallest building in the city. (Photo by Timothy A. Clary/AFP Photo)

An aerial view of the figure of a Catrina skull made with 18,000 Cempasuchil flowers (Mexican marigold) is on display at the Church of Santa Prisca as part of Day of the Dead celebrations, in Taxco, Mexico on October 27, 2021. (Photo by Daniel Cardenas/Anadolu Agency via Getty Images)

A man in Yakutsk, the capital of the Sakha Republic (Yakutia) in the Russian Far East on November 23, 2021. Located in Tuimaada Valley on the Lena River, Yakutsk is the largest city in the permafrost zone. On 23 November 2021, the daytime temperature ranged between –35 and –31 degrees Celsius in Yakutsk. On the night between 22 and 23 November, the temperature went down to –37 degrees Celsius. (Photo by Vadim Skryabin/TASS)