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)

Three prostitutes lean out of a window in Santiago, Chile, in an attempt to entice customers inside, circa 1950. (Photo by Three Lions/Getty Images)

Going nowhere in a hurry, this friendly Javan Tree frog can be seen casually hopping aboard the slow-paced snail who like a lonely highway trucker is only too happy to have the company. These cute critters chew the fat until froggy reaches his destination and alights at the top of the branch. Creative Designer and amateur photographer Kurit Afsheen (34) was able to capture this special sequence while out in his back garden in Ciledug, Indonesia. (Photo by Kurit Afsheen/Media Drum World)

This combination of August 30, 2005 and July 29, 2015 aerial photos shows downtown New Orleans and the Superdome flooded by Hurricane Katrina and the same area a decade later. Katrina's powerful winds and driving rain bore down on Louisiana on August 29, 2005. The storm caused major damage to the Gulf Coast from Texas to central Florida while powering a storm surge that breached the system of levees that were built to protect New Orleans from flooding. (Photo by David J. Phillip/Gerald Herbert/AP Photo)

A man celebrates the start of the New Year, backdropped by fireworks exploding in the background over Copacabana Beach in Rio de Janeiro, Brazil, Saturday, January 1, 2022. (Photo by Bruna Prado/AP Photo)

Mexico City resident Romina Montoya takes a playful selfie wearing a protective face mask over her eyes and nose, in Playa del Carmen, Quintana Roo state, Mexico, Wednesday, January 6, 2021. Concern is spreading that the critical winter holiday tourism success could be fleeting because it came as COVID-19 infections in both Mexico and the United States were reaching new heights. (Photo by Emilio Espejel/AP Photo)

A worker, dressed in a protective suit, cleans Conchitas Beach contaminated by an oil spill, in Ancon, Peru, Thursday, January 20, 2022. The oil spill on the Peruvian coast was caused by the waves from an eruption of an undersea volcano in the South Pacific nation of Tonga. (Photo by Martin Mejia/AP Photo)

A cat meows in it's owner's bag after fleeing from Kiev in Ukraine to Romania, following Russia's invasion of Ukraine, at the border crossing in Siret, Romania, March 10, 2022. (Photo by Clodagh Kilcoyne/Reuters)