Karis, an eleven week old lion cub, plays in fallen leaves brushed up by keepers in her enclosure at Blair Drummond Safari Park, near Stirling, Scotland, on November 20, 2013. (Photo by Andrew Milligan/PA Wire)

Three very colouful alpacas enjoy the hot weather at Toft Farm, Rugby, on July 19, 2013. (Photo by Caters News)

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)

Palestinian women wearing protective masks amid the COVID-19 pandemic pose in their traditional attire during an event to celebrate the Palestinian Traditional Dress Day and protest Israel's plan to annex parts of the occupied West Bank, in the village of Al-Jiftlik in the Jordan Valley region, on July 26, 2020. (Photo by Jaafar Ashtiyeh/AFP Photo)

A devotee throws a clay idol of Hindu elephant-headed deity Ganesh into the sea on the third day of the Ganesh Chaturthi festival, in Chennai on August 24, 2020. (Photo by Arun Sankar/AFP Photo)

Anissa Barbato from New York looks out over the city from the Edge, the highest outdoor sky deck in the Western Hemisphere on September 2, 2020 as it reopened to the public in New York. Rising 1,131 feet in the air from the heart of Hudson Yards it offers 360-degree views of New York Citys iconic skyline from the 100th floor outdoor viewing. (Photo by Timothy A. Clary/AFP Photo)

Gentoo penguins watching Christmas films at the Sea Life London aquarium on November 30, 2020. The attraction has installed two TVs, showing festive films, outside the penguin enclosure to prepare them for the stimulation of guests returning on Wednesday after the UK’s lockdown is lifted. (Photo by Yui Mok/PA Images via Getty Images)

Two citizens splash hot water which is quickly frozen in the cold air on January 7, 2021 in Beijing, China. A strong cold wave sweeps across China as the Chinese capital Beijing recorded 19.5 Celsius below zero on 06 January morning, the lowest temperature since 1966, according to meteorological authorities. (Photo by Peng Yucai/VCG via Getty Images)