“Kilauea Rules”. The most extreme place we put ours kayakers to paddle till now. Photo location: Big Island, Hawaii. (Photo and caption by Alexandre Socci/National Geographic Photo Contest)

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 pile of destroyed cars of teachers sits outside Briarwood elementary school in Oklahoma City, Oklahoma May 22, 2013. Rescue workers with sniffer dogs picked through the ruins on Wednesday to ensure no survivors remained buried after a deadly tornado left thousands homeless and trying to salvage what was left of their belongings. Curvature of horizon in the photo is due to an ultra-wide angle lens. (Photo by Rick Wilking/Reuters)

The sun rises over St Mary's Lighthouse in Whitley Bay on the Northumberland coast as a flock of Lapwing seabirds fly past on Wednesday, September 30, 2015. (Photo by Owen Humphreys/PA Wire)

Laura Halford of Wales jumps during her hoop routine as she competes in the rhythmic gymnastics individual all-around final event at the 2014 Commonwealth Games in Glasgow, Scotland, July 25, 2014. (Photo by Phil Noble/Reuters)

Genko Stoykov fires a rifle as he and other men prepare for the traditional “Horo” dance on Epiphany Day in the icy winter waters of the Tundzha river on January 6, 2022 in Kalofer, Bulgaria. As part of the tradition, a priest throws a cross in the river and it is believed that the one who retrieves it will be healthy throughout the year. Today, cultures throughout Christendom mark the Feast of the Epiphany, when Jesus was revealed to the Magi as God incarnate. (Photo by Hristo Rusev/Getty Images)

Nobby the polar bear cools down as he plays in a lake at the Yorkshire Wildlife Park in Doncaster, England, Friday June 17, 2022. A blanket of hot air stretching from the Mediterranean to the North Sea is giving much of western Europe its first heat wave of the summer, with temperatures forecast to top 30 degrees Celsius (86 degrees Fahrenheit) from Malaga to London on Friday. (Photo by Danny Lawson/PA Wire via AP Photo)

A motorway bridge crosses the icy Hunhe River in Shenyang, China on December 12, 2019. (Photo by Costfoto/Barcroft Media)