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)

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)

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)

Shan boys pray before they have their heads shaved in anticipation of their ordination in the Poy Song Long Ceremony at Wat Pa Pao in Chiang Mai, Thailand on April 3, 2018. Poy Sang Long (“The Festival of the Crystal Sons”) is a ceremony that marks a rite of passage among the Buddhist Shan people in Myanmar and northern Thailand. Boys between seven and fourteen years of age are ordained as Buddhist novices during a three day ceremony. Before the ceremony starts the boys have their heads shaved. (Photo by Jack Kurtz/ZUMA Wire/Rex Features/Shutterstock)

Seven-year-old Dihan Awallidan from Garut, West Java, is not like other boys his age. While most children crave chocolate and candy, Dihan is addicted to cigarettes. The second-grader picked up the habit at the age of 3 and now smokes up to three packs a day, using the pocket money he gets from his enabling parents to feed his addiction. (Photo by Rezza Estily/JG Photo)

Goats jumps to cross a stream as they are driven by a herdsman at Dashiwo village, on the outskirts of Beijing January 26, 2015. The Chinese Lunar New Year on February 19 will welcome the Year of the Sheep (also known as the Year of the Goat or Ram). (Photo by Kim Kyung-Hoon/Reuters)

Hundreds of green bicycles are prepared as 960 of them await riders for the new year gala at the Temple of Heaven Park on December 29, 2011 in Beijing, China. Annual New Year countdown ceremony will be held at the park on December 31. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

An employee works on a glass sphere for Christmas and New Year decoration at the “Biryusinka” toy factory, which has been producing decorations and toys for the festive season since 1942, in the Siberian city of Krasnoyarsk, Russia, November 16, 2016. (Photo by Ilya Naymushin/Reuters)