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)

Young demonstrators (many shirtless) shout and cheer as they overturn a truck trailer in the Reflecting Pool on the Mall facing the Washington Monument during the “Honor America Day Smoke-In” thrown by marijuana activists to protest the official “Honor America Day” ceremonies being held at the Lincoln Memorial, Washington, DC, July 4, 1970. (Photo by David Fenton/Getty Images)

Aymara indigenous people celebrate the “Roscasiri”, the change of command of local authorities, in Pomata District, one of seven districts of the Chucuito Province in the Puno Region, southern Peru, on January 1, 2022. This ancient Aymara event, in which people adorn themselves with breads and fruits that represent abundance for the new year, celebrates the change of command of local authorities. (Photo by Carlos Mamani/AFP Photo)

Giant pandas play in the snow at the Shenshuping Base of China Conservation and Research Center for the Giant Panda on January 13, 2022 in Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province of China. (Photo by Chen Xianlin/VCG via Getty Images)

A demonstrator uses a slingshot during a protest against Chile's government in Santiago, Chile on November 8, 2019. (Photo by Pablo Sanhueza/Reuters)

A man rides his horse next to Kosovo's coal-fired power plant near the town of Obilic on May 30, 2022. Two coal-fired power plants, Kosova A and Kosova B, are the main source of the alarming air pollution levels in Kosovo, and particularly in the town of Obilic, which is located between the two plants and near to their ash disposal sites and open-pit lignite mines. (Photo by Armend Nimani/AFP Photo)

A fantasy figure promotes a video game at the Gamescom computer gaming fair in Cologne, Germany, Thursday, August 25, 2022. Around 1,100 exhibitors from 53 countries expect tens of thousands gaming enthusiast daily for the first time since the COVID-19 pandemic at the world's largest gaming event. (Photo by Martin Meissner/AP Photo)

A flood affected family moves on a banana raft past a fishing net in Morigaon district, east of Gauhati, northeastern Assam state, India, Sunday, July 31, 2016. A week of heavy rain has killed dozens of people and uprooted tens of thousands of others from their homes. Floods are an annual occurrence in Assam and many parts of India during the June-September monsoon season. (Photo by Anupam Nath/AP Photo)