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)

In this handout image provided by Red Bull, Artem Silchenko of Russia dives from the 27 metre platform at training on Hong Island in the Andaman Sea during the final stop of the 2013 Red Bull Cliff Diving World Series on October 25, 2013 at Krabi, Thailand. (Photo by Romina Amato/Red Bull via Getty Images)

Members of the King's Troop Royal Horse Artillery fire a 41 gun salute in Hyde Park to mark the 60 anniversary of the accession of Her Majesty Queen Elizabeth II on February 6, 2012 in London, England. (Photo by Oli Scarff/Getty Images)

The coffin containing the body of Pope John Paul II is exhumed ahead of his beatification at Vatican Basilica on April 29, 2011 in Vatican City, Vatican. Pope John Paul II will be beatified by Benedict XVI in a ceremony at the Vatican on Sunday. (Photo by Pool/Getty Images)

Students from John Moores' University celebrate and pose for family photographs as they take part in their degree congregations at Liverpool's Anglican Cathedral on July 13, 2011 in Liverpool, England. Thousands of students are taking part in graduations across Britain and will begin looking for employment. According to recent surveys there are currently 83 graduates chasing every job vacancy. (Photo by Christopher Furlong/Getty Images)

This image released by Paramount Pictures shows Taron Egerton as Elton John in a scene from “Rocketman”. (Photo by David Appleby/Paramount Pictures via AP Photo)

US actress Vanessa Hudgens poses upon her arrival for the 25th annual Elton John AIDS Foundation's Academy Awards Viewing Party on February 26, 2017 in West Hollywood, California. (Photo by Tibrina Hobson/AFP Photo)

Daredevil Christopher Gillette writhes around with a huge alligator he has saved from death. He works at a Florida sanctuary that rescues the wild beasts if they stroll into neighbourhoods where residents can legally kill them. To raise cash for the centre at Homestead, staff put on shows to feed and wrestle the alligators. Photographer John Chapa, 41, and girlfriend Adriana Canargo, 30, took these shots. Photo: Assistant photographer Adriana Canargo dives with a wild alligator. (Photo by John Chapa/Barcroft Media)