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 vendor smokes behind a display of dog meat at a dog meat market on the day of a local dog meat festival in Yulin, Guangxi Autonomous Region, June 22, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Shemika Charles limbos under her car at Niagara Falls State Park on May 28, 2015 in Buffalo, New York. A world record holding limbo queen thinks she has become the first person to shimmy under a car. Shemika Charles amazed herself and onlookers when she bent over backwards to get underneath the SUV earlier this week. The supple 22-year-old entered the record books in 2010 when she limboed down to an incredible eight and a half inches – the height of a beer bottle. She trains for up to four hours a day to keep her body in peak condition and now travels around America performing with her family. However, regular performances put an incredible strain on her body and she sees a chiropractor once a week to have her hips realigned. Her mother was also a successful limbo dancer in her home country of Trinidad and Tobago but had to give up due to injury. (Photo by Ruaridh Connellan/Barcroft USA)

French National Front party deputy Marion Marechal-Le Pen attends the questions to the government session at the National Assembly in Paris April 14, 2015. (Photo by Charles Platiau/Reuters)

Vanessa, thirty-five, had three children with an abusive husband. She “lost her mind, started doing heroin”, after losing the children, who were taken away and given to her mother. The drugs led to homelessness and prostitution. She grew up on Arthur Avenue in the Bronx, but now spends her time in Hunts Point, “trying to survive everyday. Just doing whatever it takes”.

“Attacking Howler Monkey”. Due to a major tropical rainstorm my wife and I were forced to stay overnight in a Howler Monkey Rescue center in Panama. I used the time to explore the area and to take photos of the monkeys. Just after the rain finally stopped, I ran into this monkey that tried to mock attack me. I quickly took a couple of photos before retreating to a (more) safe distance. (Photo and caption by Christian Mueller-Planitz/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

People ride a motorcycle near Koudoukou Mosque where Pope Francis meets Imam Tidiani Moussa Naibi in Bangui, Central African Republic, November 30, 2015. (Photo by Stefano Rellandini/Reuters)

Children of Indian laborers play on make-shift swings in Amritsar, India, May 12, 2015. (Photo by Narinder Nanu/AFP Photo)