A visitor tries a baccarat game at the Global Gaming Expo (G2E) Asia in Macau, China May 19, 2015. (Photo by Bobby Yip/Reuters)

Roman Amoyan of Armenia, bottom, and Elman Mukhtarov of Azerbaijan compete in the the Men's wrestling, 59kg Greco-Roman Bronze Medal event at the 2015 European Games in Baku, Azerbaijan, Saturday, June 13, 2015. (AP Photo/Dmitry Lovetsky)

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 tunnel with electric switches are seen in Josip Broz Tito's underground secret bunker (ARK) in Konjic, October 16, 2014. In the early 1950s, Josip Broz Tito, the late leader of the former Yugoslavia, ordered the building of the secret bunker, located 900 feet (270 m) underground and near the Bosnian town of Konjic, to safeguard the country's ruling class in case of a nuclear attack. Construction at the complex, which had a cost equivalent price tag of $4.6 billion, continued until 1979, the year before Tito died. (Photo by Dado Ruvic/Reuters)

Wing maker Marian Hose (L), also known as “Killer”, and Model Martha Hunt take part in a fitting ahead of the Victoria's Secret fashion show in New York, U.S., October 30, 2018. (Photo by Kevin Coombs/Reuters)

Bella Hadid prepares backstage during 2018 Victoria's Secret Fashion Show in New York at Pier 94 on November 8, 2018 in New York City. (Photo by Dia Dipasupil/Getty Images for Victoria's Secret)

Candice Swanepoel attends the Victoria's Secret Very s*xy Tour Stop in Dallas at Victoria's Secret Beauty at the NorthPark Mall on March 22, 2012 in Dallas, Texas. (Photo by Peter Larsen/ Getty Images for Victoria's Secret)

Model Alessandra Ambrosio (L) and Adriana Lima walk the runway during the 2011 Victoria's Secret Fashion Show at the Lexington Avenue Armory on November 9, 2011 in New York City. (Photo by Jamie McCarthy/Getty Images)