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)

A man in a Donald Trump mask joins hundreds of other protesters and activists as they march during a demonstration near a midtown hotel which is hosting a black-tie fund-raiser for the state Republican Party on April 14, 2016 in New York City. (Photo by Spencer Platt/Getty Images)

A woman smokes a cigar as she reads the newspaper in a street of Havana, on November 26, 2016, the day after Cuban revolutionary leader Fidel Castro died aged 90. One of the world's longest-serving rulers and modern history's most singular characters, Castro defied 11 US administrations and hundreds of assassination attempts. (Photo by Yamil Lage/AFP Photo)

A Pakistani devotee dances to celebrate the three-day annual festival to pay tribute to the famous saint Al-Sheikh Ali Bin Usman Al-Hajveri known as Data Ganjbaksh at outside his shrine in Lahore, Pakistan, Sunday, November 20, 2016. Thousands of people traveled from all over Pakistan to attend the celebrations. (Photo by K.M. Chaudary/AP Photo)

A man covered with thermal blanket walks along railway tracks beside an improvised refugee camp on the border line between Macedonia and Serbia near the northern Macedonian village of Tabanovce, Thursday, March 10, 2016. Around 1.500 migrants and refugees are stranded at Tabanovce transit center for refugees in northern Macedonia. (Photo by Boris Grdanoski/AP Photo)

Tomomi Ota pushes a trolley loaded with her humanoid robot Pepper as she crosses a street in Omotesando shopping district in Tokyo, Japan, 24 March 2016. Telecommunications and mobile phone carrier SoftBank Corp. opened a robot-staffed store where 10 Pepper humanoid robots welcome customers looking to buy a mobile phone. The store will be opened until 30 March 2016. (Photo by Franck Robichon/EPA)

Young girls carry containers filled with drinking water beside the railway station in Agartala, India, April 20, 2016. (Photo by Jayanta Dey/Reuters)

A worker at the Jabal Saraj cement factory poses for a photograph in Jabal Saraj, north of Kabul, Afghanistan April 19, 2016. In an area desperately short of industry and jobs, local workers hope that the relaunch of the plant in Jabal Saraj, built by Czech engineers in 1957 and closed down by the Taliban in 1995, can show that Afghanistan's shattered industry can climb back to its feet after decades of war and destruction. But the outdated state-owned plant some 75 kilometres outside Kabul also shows how far it has to go before that promise can be achieved and there are serious questions over whether it has a viable future unless a new, modern facility is built to replace it. (Photo by Ahmad Masood/Reuters)