In this photograph taken on April 16, 2014, a veterinary staff member of the Sumatran Orangutan Conservation Programme center conducts medical examinations on a 14-year-old male orangutan found with air gun metal pellets embedded in his body in Sibolangit district in northern Sumatra island. (Photo by Sutanta Aditya/AFP Photo)

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)

Two three-month-old female white Bengal tiger cubs play with a zoo keeper in their enclosure at the Buenos Aires' Zoo, in Argentina, on April 17, 2014. Captive white Bengal tiger Cloe, gave birth to three cubs – two females and one male – on January 14, 2014. (Photo by Juan Mabromata/AFP Photo)

Carolaine Reis and her son Miguel Alves, residents of the Aglomerado da Serra favela, wear a protective mask against the spread of the new Coronavirus (COVID-19) made by the seamstresses of the Remexe Favelinha studio, in the Aglomerado da Serra favela, on April 13, 2020 in Belo Horizonte, Brazil. Facial masks follow the protocol and guidelines defined by the Ministry of Health. Around 6,000 masks have already been produced. The masks are being distributed to a part of the population and sold throughout the country, in the amount of 5 reais per unit. (Photo by Pedro Vilela/Getty Images)

A boy flies his kite in a cemetery in the Vila Operaria Favela of Rio de Janeiro, Brazil, July 9, 2016. (Photo by Nacho Doce/Reuters)

A teenage girl from the Santa Marta favela slum puts on a pair of high heels for a group debutante ball organized by the Pacifying Police Unit from her neighborhood in Rio de Janeiro, Brazil, Friday, August 29, 2014. The ball, which relied on volunteers who coiffed and made up the girls and a formal wear shop that loaned the dresses, helped build goodwill between pacified favelas' residents and the officers who patrol them. (Photo by Silvia Izquierdo/AP Photo via The Palm Beach Post)

A member of the Acorda Capoeira (Awaken Capoeira) group performs on a rooftop in the Rocinha favela in Rio de Janeiro, Brazil, July 24, 2016. In a favela with a history of violence between police and drug gangs, or armed battles between traffickers themselves, capoeira is an outlet that gives kids a sense of community – its practice a collective exercise blending characteristics of drum circles, sparring and tag-team gymnastics. (Photo by Bruno Kelly/Reuters)

Rio de Janeiro's state military policemen aim their guns during a violent protest in a favela next to Copacabana, Rio de Janeiro on April 22, 2014. Violent protests broke out in Rio's landmark beachfront district, Copacabana, following the death of a resident last weekend during clashes with the Army in a nearby favela. (Photo by Christophe Simon/AFP Photo)