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 Tuesday, July 14, 2015, photo, Phoe Thaw, center, a member of the White New Blood lethwei fighters club, a Myanmar traditional martial-arts club which practices a rough form of kickboxing, stretches during a practice session in their gym on a street in Oakalarpa, north of Yangon, Myanmar. Three of the club's members competed this summer on a stage a world away from the street gym: a mixed-martial-arts “One Championship” event broadcast globally on cable television networks, where fighters could receive $1,000 for each fight, according to coach Myint Zaw who started the traditional fighters' club 15 years ago. (Photo by Gemunu Amarasinghe/AP Photo)

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

President Donald Trump speaks at a campaign rally at Duluth International Airport, Wednesday, September 30, 2020, in Duluth, Minn. (Photo by Alex Brandon/AP Photo)

Lightning over Mow Cop Castle which is a folly at Mow Cop in the civil parish of Odd Rode, Cheshire, UK on August 13, 2020, as thunderstorms continue during the current heatwave. (Photo by Lee Scally/Bav Media)

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)

Overall winner: The Art of Flight by Alwin Hardenbol (University of Eastern Finland). A panning shot of a Dalmatian pelican in flight. The picture was taken on Lake Kerkini in Greece. (Photo by Alwin Hardenbol/2020 British Ecological Society Photography Competition)

The Taal Volcano in the central Philippines boomed to life on Sunday, January 12, 2020 spilling ash and causing evacuations in nearby communities – and officials warn that a more powerful eruption is imminent. One of the world’s smallest volcanoes, Taal is among two dozen active volcanoes in the Philippines, which lies along the so-called Pacific Ring of Fire, a seismically active region that is prone to earthquakes and volcanic eruptions. (Photo by Kester Ragaza/Pacific Press/Rex Features/Shutterstock)