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)

Soniya, 6, whose family moved to Islamabad from Pakistan's Khyber-Pakhtunkhwa province to look for work, stands outside their house on the outskirts of Islamabad January 1, 2015. (Photo by Zohra Bensemra/Reuters)

New York Police officers arrest a drag queen during a weekly “We Choose Freedom” march through the West Village, Thursday, November 5, 2020, in New York. (Photo by Seth Wenig/AP Photo)

Joseph Fons holding a Pride Flag, runs in front of the U.S. Supreme Court building after the court ruled that a federal law banning workplace discrimination also covers sexual orientation, in Washington, D.C., U.S., June 15, 2020. (Photo by Tom Brenner/Reuters)

A military helicopter flies over people during the Afghan Security Forces Exhibition, at the Darul Aman Palace in Kabul, Afghanistan, Wednesday, March 3, 2021. The three-day military exhibition in Kabul allowed civilians to have a first hand view and take pictures of weaponry used by Afghan Security forces. (Photo by Rahmat Gul/AP Photo)

A stunt rider performs on the wooden wall during a fair in Bogra, Bangladesh, February 10, 2021. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

Party-loving Brits headed out to enjoy the first weekend of indoor drinking in months; many – like these lasses in Liverpool on May 22, 2021 – were keen to make up for lost time. (Photo by London News Pictures)

Fishermen are seen near thousands of fish found dead at Lake Maninjau due to lack of oxygen levels at the bottom of the lake and bad weather that hit the area in Agam, West Sumatra Province, Indonesia on April 29, 2021. (Photo by Muhammad Arif Pribadi/Antara Foto via Reuters)