Revelers celebrate during fireworks marking the start of the New Year on Copacabana beach on January 1, 2017 in Rio de Janeiro, Brazil. Brazilian revelers traditionally dress in white to honor the New Year's holiday along with the Brazilian Goddess of the Sea- Iemanja. (Photo by Mario Tama/Getty Images)

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)

Gertrude “Billie” Murphy, 22, is brought in for questioning in the murder case of Michael Stopec, who was shot and killed in an apartment hotel, circa July 1927. Murphy had been friends of the married Stopec and his suspected killer Henry Guardino, 31. It is said that Stopec and Guardino were “bitter rivals for the favor of Billie” and that Murphy had tired of Guardino and was going to stay with Stopec. Murphy was also married to a man in the Joliet penitentiary. (Photo by Chicago Herald & Examiner Historical Photo)

Vegetarian 19-year-old model Courtney Stodden gets ready to serve veggie hot dogs wearing a lettuce bikini during a People for the Ethical Treatment of Animals (PETA) free veggie dog handout on Capitol Hill in Washington, DC, July 16, 2014. (Photo by Jim Watson/AFP Photo)

Mahouts return home with their elephants carrying grass to feed them on the eve of the rhino census in Kaziranga National Park in Assam state, India, 24 March 2015. Kaziranga will be closed to visitors for the next two days for a census of the rhinos commencing 25 March, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

Vehicles move past a man resting on a taxi, as he waits for passengers, along a road in Karachi, Pakistan, May 5, 2015. (Photo by Akhtar Soomro/Reuters)

Revellers enjoy the atmosphere during the opening day or “Chupinazo” of the San Fermin Running of the Bulls fiesta on July 6, 2015 in Pamplona, Spain. The annual Fiesta de San Fermin, made famous by the 1926 novel of US writer Ernest Hemmingway entitled “The Sun Also Rises”, involves the daily running of the bulls through the historic heart of Pamplona to the bull ring. (Photo by Pablo Blazquez Dominguez/Getty Images)