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 three-month-old Sumatran tiger cub named “Bandar” shows his displeasure after being dunked in the tiger exhibit moat for a swim reliability test at the National Zoo in Washington, on November 6, 2013. All cubs born at the zoo must take a swim test before being allowed to roam in the exhibit. Bandar passed his test. (Photo by Manuel Balce Ceneta/Associated Press)

A grey squirrel looks for some food from a girl in the Botanic Gardens in Glasnevin, Dublin, Ireland on April 3, 2023. (Photo by Damien Eagers/The Irish Times)

A Palestinian employee sprays antibiotics on a newborn lion cub at Nama zoo in Gaza City, Saturday, August 13, 2022. Three one-day-old lion cubs were put on display inside a cardboard box Saturday at a Gaza City zoo. The lioness gave birth five days after Israel and Palestinian militants ended a fierce round of cross-border fighting that saw thundering Israeli airstrikes and Palestinian rocket fire. (Photo by Fatima Shbair/AP Photo)

A local resident dressed as Yamraj or Hindu god of death, wearing a novel coronavirus-themed balloon necklace, gestures as he poses during an awareness about social distancing and staying at home organised by Delhi police during a nationwide lockdown to slow the spreading of the coronavirus disease (COVID-19), in New Delhi, India, April 28, 2020. (Photo by Adnan Abidi/Reuters)

A girl with a ritual garland headdress smiles during a traditional Midsummer Night celebration, in the capital Kyiv, Ukraine, Monday, July 6, 2020. Ukrainian girls believe the ages-old ceremony would help them to find their true love partners, as the pagan Slav festival is still celebrated in Ukraine, as Kyiv has lifted the coronavirus lockdown restrictions. (Photo by Efrem Lukatsky/AP Photo)

Russia' s President Vladimir Putin (L) congratulates prizewinners at the 2018 Youth Judo Tournament dedicated to Soviet and Russian judo coach Anatoly Rakhlin, and held at St Petersburg' s Yubileyny Palace of Sports in St Petersburg, Russia on May 23, 2018. (Photo by Mikhail Metzel/TASS)