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)

“By 1969, the fashion choices of tens of millions of young American men and women were as variegated and ever-evolving as the world around them. Cultural transformation was an irresistible force during the Sixties, and across America and around the globe civil rights, women’s and gay liberation, the sexual revolution and, of course, the explosive soundtrack of R&B, soul and rock and roll informed everything from politics to fashion”. – LIFE. Photo: Corona del Mar High School students Kim Robertson, Pat Auvenshine and Pam Pepin wear “hippie” fashions, 1969. (Photo by Arthur Schatz/Time & Life Pictures)

The goats are known to be good climbers, but this one is taking the climbing thing to a whole new level. It clambered on the tip of its owner’s stick, as a part of the roadside performance for a quick coin, on the outskirts of Faisalabad, Pakistan, November 5, 2012. (Photo by Fayyaz Hussain/Reuters)

A stork-billed kingfisher (Pelargopsis capensis) is seen perched on a tree during monsoon rain on July 25, 2016 in Bintan, Indonesia. The stork-billed kingfisher is a tree species which is widely but sparsely distributed in the tropical Indian subcontinent and Southeast Asia, from India to Indonesia. This kingfisher is resident throughout its range. It is very large, measuring 35 to 38 cm (14 to 15 in) in length. The adult has a green back, blue wings and tail, and grey head. (Photo by Sijori Images/Barcroft Images)

A reporter takes pictures of a soldier during the annual Han Kuang military exercise in Kinmen, Taiwan, September 7, 2015. Rustic Kinmen, with a population of less than 129,000, is a half-hour ferry ride to China, but it takes an hour to fly to major Taiwan cities. Just off its shores, glass-walled high-rises wink seductively from the booming mainland port of Xiamen in one of China's most prosperous provinces. (Photo by Pichi Chuang/Reuters)

Chris Renshaw has recently been awarded the 2015 Africa Geographic “Photographer of the Year” award. Chris tells that his love “for anything wild and adventurous came from a deep rooted attachment to the African continent. This image shows that timing, a bit of anticipation, and luck allowed this incredible moment in time to be captured”. (Photo by Chris Renshaw)

The moon rises behind Reunion Tower in downtown Dallas, Sunday evening, November 13, 2016. On Monday the supermoon will be the closest full moon to earth since 1948, and it won't be as close again until 2034. (Photo by Tom Fox/The Dallas Morning News via AP Photo)

An environmental activist adjusts his mask while taking part in “The Dead Sea Swim Challenge”, swimming from the Jordanian to Israeli shore, to draw attention to the ecological threats facing the Dead Sea, in Kibbutz Ein Gedi, Israel November 15, 2016. Swimmers from around the world plunged into the salty waters of the Dead Sea on Tuesday to attempt a seven-hour swim across the fabled lake in a bid to draw attention to its environmental degradation. Wearing protective masks and snorkels, 25 swimmers paddled through the muddy water to attempt the 9-mile (15-kilometer) swim from Jordan to Israel. (Photo by Nir Elias/Reuters)