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)

“Left behind” children Luo Hongni, 11 (L) and brother Luo Gan,10, carry flowers to be used as feed while doing chores in the fields on December 18, 2016 in Anshun, China. Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. (Photo by Kevin Frayer/Getty Images)

Nutrias venture near the camera at the river Nidda in Frankfurt am Main, Germany, 15 June 2017. The rabbit sized animals are often confused with biebers by amateurs. (Photo by Boris Roessler/DPA)

A winter swimmer jumps into a pool in the frozen Songhua River during an activity for welcoming the Chinese New Year on January 30, 2022 in Harbin, Heilongjiang Province of China. (Photo by Liu Yang/VCG via Getty Images)

French artist Gino rides the “Celestial Cyclo” tricycle built by him in Le Marais neighbourhood in Paris, France, August 15, 2015. (Photo by Pascal Rossignol/Reuters)

A pod of white pelicans, one of the largest birds in Canada and the US, are seen on the shore of the Chapala lagoon in Cojumatlan de Regules, Mexico, on January 28, 2022. White pelicans travel thousands of kilometers migrating from the cold temperatures of North America. (Photo by Ulises Ruiz/AFP Photo)

Ana Paula Santos sunbathes in a bikini top fashioned from electrical tape at the Sabrina Bronze rooftop salon which offers crisp tan lines in the Turano favela of Rio de Janeiro, Brazil, Thursday, January 27, 2022. Santos said she uses the rooftop partially because she prefers its privacy compared to the public beach. (Photo by Silvia Izquierdo/AP Photo)

Visitors look out from a balcony in a quiet mall area with closed retail shops and restaurants only offering takeaway on Tuesday, May 10, 2022, in Beijing. China's capital began another round of three days of mass testing for millions of its residents Tuesday in a bid to prevent an outbreak from growing to Shanghai proportions. (Photo by Ng Han Guan/AP Photo)