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)

Ratko Mladic makes his first appearance at the International Criminal Tribunal on June 3, 2011 in The Hague, Netherlands. Ex-Bosnian Serb army leader Ratko Mladic will make his first appearance at The Hague war crimes tribunal after being declared fit to stand trial. Mladic was arrested a week ago after going into hiding for the past 16 years and is charged with atrocities committed during the Bosnian war. (Photo Serge Ligtenberg/Getty Images )

“Wells Cathedral is a Church of England cathedral in Wells, Somerset, England. Built between 1175 and 1490, Wells Cathedral has been described as “the most poetic of the English Cathedrals”. The Wells clock, an astronomical clock, is located in the north transept. The surviving mechanism, dated to between 1386 and 1392, was replaced in the 19th century, and was eventually moved to the Science Museum in London, where it continues to operate. It is the second-oldest surviving clock in England”. – Wikipedia

Photo: The clock face of world's oldest continually-working mechanical clock is seen as it is hand wound for the very last time on August 21, 2010 in Wells, England. (Photo by Matt Cardy/Getty Images)

Philippe Marquis of Canada during the FIS Freestyle Ski World Cup Dual Moguls on December 20, 2011 in Meribel, France. (Photo by Alain Grosclaude/Agence Zoom/Getty Images)

“A dazzling exhibition featuring jewelry made with the world’s largest diamond will be part of the celebrations marking the 60th anniversary of Queen Elizabeth II’s reign. The jewelry was made with a 3,106-carat diamond discovered in 1905 at the Cullinan Diamond Mine near Pretoria, the capital of South Africa. The diamond was so large that miners initially thought it was a worthless crystal and almost threw it away”... – Vidya Kauri via News.nationalpost.com

Photo: Caroline de Guitaut, Curator of Royal Collections, holds the Cullinan III and IV Broach and the Cullinan VII Delhi Durbar Necklace and Cullinan Pendant at The Queen's Gallery, Buckingham Palace on May 15, 2012 in London, England. (Photo by Peter Macdiarmid)

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)