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 woman receives a traditional cleansing in the church of San Simon in Iztapa, Chimaltenango, Guatemala, October 28, 2015. People in Guatemala revere San Simon, also known by his Mayan name Maximon o Ry Laj Man, on October 28 annually. For some devotees, San Simon is synonymous with prosperity and happiness, while others associate him with witchcraft, paganism and a protector for drunkards. Since the 19th century, devotees have offered money, liquor or tobacco in exchange for his blessings. (Photo by Jorge Dan Lopez/Reuters)

Invented in 1920′s this could be world’s first navigation system. No satellites or digital screens were used in the making of this portable navigation system. Called Plus Fours Routefinder, this little invention was designed to be worn on your wrist, and the “maps” were printed on little wooden rollers which you would turn manually as you drove along.

Pilots plan a flight manoeuvre with model aircraft at a military air base in Vasylkiv, Ukraine, August 3, 2016. (Photo by Gleb Garanich/Reuters)

Singer Shania Twain is honored with the 2442nd Star on the Hollywood Walk Of Fame on June 2, 2011 in Hollywood, California. (Photo by Jason Merritt/Getty Images)

A general view of the landslide-hit Miancu Village on July 3, 2011 in Maixian County, Sichuan Province of China. Eight people are still missing after a dormitory building of a chemical plant was hit by a rain-triggered mudslide in Maoxian County on Sunday morning. Rescue efforts are underway. (Photo by ChinaFotoPress/Getty Images)

Japanese toy maker Takara Tomy's world's smallest humanoid robot “i-Sobot” is displayed during the Toy Forum 2007 on January 23, 2007 in Tokyo, Japan. The 165mm height robot is able to walk, play the drums and keep its balance. (Photo by Koichi Kamoshida/Getty Images)