Visitors gather outside Ark Encounter, a 100 million USD, 510-foot-long re-creation of Noah's Ark in Williamstown Kentucky, USA, 05 July 2016. Ark Encounter is the brainchild of Australian-born creationist Ken Ham; it was built with the help of state tax incentives and the sale of 62 million USD in junk bonds. (Photo by Jim Lo Scalzo/EPA)

In this photograph taken on Thursday, November 20, 2014, bud tenders Maxwell Bradford, back left, and Emma Attolini display buds in the shape of Christmas trees that are on sale for the holiday season in a recreational marijuana shop in northwest Denver. The nascent marijuana industry in Colorado is targeting holiday shoppers with special deals much like traditional retailers offer. (Photo by David Zalubowski/AP Photo)

Four men ride a motorbike past sacrificial animals displayed for sale ahead of the Eid al-Adha festival at a livestock market in Sana'a, Yemen, 08 August 2019. Eid al-Adha is the holiest of the two Muslims holidays celebrated each year; it marks the yearly Muslim pilgrimage (Hajj) to visit Mecca, Islam's holiest place. Muslims slaughter a sacrificial animal and split the meat into three parts: one for family, one for friends and relatives, and one for the poor and needy. (Photo by Yahya Arhab/EPA/EFE)

Vintage car enthusiast Peter Bett, attends a auction at Strathmore Vintage Vehicle Club on April 2, 2011 in Glamis, Scotland. Buyers from around the UK and Europe are attending the auction of cars collected by William Cunnigham. Among the many rare classics on sale is a 1939 McEvoy Steyr, thought to be the only one in existence along with a Hotchkiss Grand Sport Roadster from 1936. (Photo by Jeff J Mitchell/Getty Images)

The new Toyota Camry Hybrid LE is parked next to the redesigned 2012 Camry SE after the unveiling event on the Paramount Studios lot on August 23, 2011 in Hollywood, California. The five-seat Camry SE and the Hybrid XLE sedans go on sale in December. (Photo by Kevork Djansezian/Getty Images)

A person stands near the “Untitled” installation of miniature elevators by Maurizio Cattelan at a preview of the Postwar and Contemporary Art Evening Sale at Christie's auction house on November 4, 2011 in New York City. The 33-inch functioning elevator installation is expected to realize $400,000-$600,000 at the November 8 auction. (Photo by Mario Tama/Getty Images)

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)