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 Thai performer puts his head inside a crocodile's mouth during a media preview performance as part of preparation to reopen Samutprakarn Crocodile Farm and Zoo in Samut Prakan province, Thailand, 19 March 2024. (Photo by Rungroj Yongrit/EPA)

People search for shells on a beach in Sittwe, Rakhine State, Myanmar, 17 September 2020. International Coastal Cleanup Day is observed annually on the third Saturday of September and will occur on 19 September this year. (Photo by Nyunt Win/EPA/EFE/Rex Features/Shutterstock)

Bottles of vintage cognac, with a royal warrant stamp, are seen in storage inside Berry Bros and Rudd wine merchants in central London, Britain, August 21, 2015. Berry Bros. & Rudd, which started as grocers over 300 years ago in St. James's, central London, has two royal warrants. Every year Queen Elizabeth grants about 20 royal warrants, the gold emblem of the British monarchy, in a practice dating back to medieval times. The warrant holders can display the certificate and use the royal coat of arms in their marketing. The warrants lasting five years can help businesses break into new markets overseas, using their role as supplier to the royal family as a gauge of quality. On September 9, Queen Elizabeth will overtake Queen Victoria as Britain's longest-serving monarch. (Photo by Toby Melville/Reuters)

American singer Tinashe arrives at the 2022 American Music Awards at the Microsoft Theater, in Los Angeles, California, U.S., November 20, 2022. (Photo by Aude Guerrucci/Reuters)

Jesse Larios, 33, from Los Angeles, wears a bear suit while walking along Hollister Road in Gilroy, California, U.S., April 21, 2021. Larios, also known as Bear Sun on social media, is walking from his home in Los Angeles to San Francisco while wearing the bear suit as a social media fundraising event. (Photo by Brittany Hosea-Small/Reuters)

Tercio Galdino, 66, and his wife Aliceia, 65, wear their protective “space suits” as they walk on the sidewalk of Copacabana Beach amid the coronavirus outbreak in Rio de Janeiro, Brazil, July 11, 2020. (Photo by Ricardo Moraes/Reuters)

Women wearing traditional attire take a selfie as they practice the Garba, the traditional dance of Gujarat state, ahead of Navratri in Ahmedabad, India, Tuesday, September 20, 2022. The Hindu festival of Navratri, or nine nights, will begin Sept. 26. (Photo by Ajit Solanki/AP Photo)