A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)

Russian artist Maria Gazanova (L) works on her "The Alive Painting" art work during the Art Krasnoyarsk annual festival in Siberian city of Krasnoyarsk, Russia November 4, 2015. (Photo by Ilya Naymushin/Reuters)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

In this March 18, 2015 photo, Andrea, better known as Loira, which is the Portuguese word for “blonde”, poses for a portrait in an open-air crack cocaine market, known as a “cracolandia” or crackland where users can buy crack, and smoke it in plain sight, day or night, in Rio de Janeiro, Brazil. Andrea says she is married and has a home, but she keeps returning to crackland to feed her addiction. (Photo by Felipe Dana/AP 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)

A protestor confronts police and National Guard troops near the Wauwatosa City Hal on October 09, 2020 in Wauwatosa, Wisconsin. The city has faced three days of demonstrations, prompting a 7 PM curfew, after District Attorney John Chisholm refused to press charges against Wauwatosa Police Officer Joseph Mensah for the Feb. 2 fatal shooting of 17-year-old Alvin Cole. (Photo by Scott Olson/Getty Images)

Bianca Toniolo picks a daisy as the family take a walk through the woods 200 metres from their home in San Fiorano, March 19, 2020. This was the last time the family went to the woods as restrictions got stricter throughout the country to try and contain the spread of coronavirus. (Photo by Marzio Toniolo/Reuters)

A woman returns home carrying vegetable on her back (foreground) while other farmer works on vegetable field (background) during the 43rd day of the lockdown imposed by the government as a preventive measure against the spread of COVID-19 coronavirus, in Kathmandu, Nepal on Tuesday, May 5, 2020. (Photo by Rojan Shrestha/NurPhoto via Getty Images)