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)

Fighters from Germany take up position before competing in the Medieval Combat World Championship at Malbork Castle, northern Poland, April 30, 2015. Medieval combat is a full contact sport that revives the foot based tournament fighting of medieval Europe. Countries fight in refereed matches where the objective is to get the opposing team to the floor. There are also duels with polearms, swords and shields where the number of hits landed are scored. The fighters, both male and female, wear heavy armours and weapons, mostly replicas of authentic pieces, and fight following the knights code of conduct. According to organizers, 25 nations from 6 continents are taking part in the Championships, which started on April 30 and will go on until May 3. (Photo by Kacper Pempel/Reuters)

Lava erupts from the Piton de la Fournaise “Peak of the Furnace” volcano, on the southeastern corner of the Indian Ocean island of Reunion Saturday, August 1, 2015. Spewing red-hot lava, one of the most active volcanoes in the world is currently erupting on this Indian Ocean island, where the world's attention has been focused since a wing fragment believed to be from the missing Malaysian jet was discovered washed up on a beach. The lava fountains are shooting as high as 40 meters (44 yards) and are creating cones that are about 20 meters high after only one day of eruption, said Peltier. The volcano is in the Reunion National Park – a world heritage site. The volcano is not seen as dangerous because the lava flows down the east side of the mountain through an uninhabited area called the Grand Brule, or the Big Burned, toward the sea. The last times the volcano threatened the population was in 1977 and 1986. (Photo by Ben Curtis/AP Photo)

Tiffany Porter of Britain falls after competing in the women's 100 metres hurdles final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 28, 2015. (Photo by David Gray/Reuters)

Second placed Zhang Guowei of China gestures as he celebrates after winning silver in the men's high jump final during the 15th IAAF World Championships at the National Stadium in Beijing, China, August 30, 2015. (Photo by Dylan Martinez/Reuters)

Leopard seal chasing a Gentoo penguin in Antarctica. This image wins the gold prize in the behaviour – mammals category, and the grand prize of World Nature Photographer of the Year. (Photo by Amos Nachoum/World Nature Photography Awards)

A masked tourist poses for a souvenir photo next to a graffiti titled “Mobile World Virus” depicting “La Gioconda”, aka Mona Lisa, with a mobile phone and a medical mask, by urban artist TVBoy, close to the Sant Jaume square in Barcelona, Spain, 09 March 2020. Barcelona's Deputy Mayor and two town councillors are in quarantine after they were in contact with a City Hall's worker who was tested positive for the COVID-19 coronavirus. (Photo by Quique Garcia/EPA/EFE)

A US soccer fan cheers during the FIFA World Cup 2014 group A preliminary round match between Brazil and Croatia at the FIFA Fan Fest in Copacabana, Rio de Janeiro, Brazil, 12 June 2014. Brazil won 3-1. The FIFA World Cup 2014 will take place in Brazil from 12 June to 13 July 2014. (Photo by Abedin Taherkenareh/EPA)