“North and South Korea staged dueling war games Monday as threatening rhetoric from the rivals rose to the highest level since North Korea rained artillery shells on a South Korean island in 2010”. – Associated Press. Photo: North Korean soldiers with weapons attend military training in an undisclosed location in this picture released by the North’s official KCNA news agency in Pyongyang March 11, 2013. South Korea and U.S. forces are conducting large-scale military drills until the end of April, while the North is also gearing up for a massive state-wide military exercise. North Korea has accused the U.S. of using the military drills in South Korea as a launch pad for a nuclear war and has threatened to scrap the armistice with Washington that ended the 1950-53 Korean War. (Photo by KCNA/Reuters)

Runners gather at the start line for the annual “Santa Speedo Run”, a charity race through the streets of the Back Bay neighborhood of Boston. (Photo by Gretchen Ertl/Reuters)

“By 1969, the fashion choices of tens of millions of young American men and women were as variegated and ever-evolving as the world around them. Cultural transformation was an irresistible force during the Sixties, and across America and around the globe civil rights, women’s and gay liberation, the sexual revolution and, of course, the explosive soundtrack of R&B, soul and rock and roll informed everything from politics to fashion”. – LIFE. Photo: Corona del Mar High School students Kim Robertson, Pat Auvenshine and Pam Pepin wear “hippie” fashions, 1969. (Photo by Arthur Schatz/Time & Life Pictures)

In this June 8, 2015 photo, Omkarnath, who goes by the name “Medicine Baba”, pays his reverence at a neighborhood temple as he begins his day in New Delhi, India. The chatty, 79-year-old retired blood-bank technician has been collecting unused prescription drugs from the affluent for the past eight years, and distributing whatever hasn't expired to patients who need medicines they cannot afford. (Photo by Saurabh Das/AP Photo)

In this January 6, 2017 photo, transgender inmates get a security check from female officers before entering their cell at Pattaya Remand Prison in Pattaya, Chonburi province, Thailand. The prison separates lesbian, gay, bisexual and transgender prisoners from other inmates, a little-known policy despite being in place nationwide since 1993, according to the Department of Corrections. (Photo by Sakchai Lalit/AP Photo)

An Israeli spectator watches a giant T-Rex balloon during the Purim parade festival in Petah Tikva, Israel, Thursday, March 24, 2016. The Jewish holiday of Purim commemorates the Jews' salvation from genocide in ancient Persia, as recounted in the Book of Esther. (Photo by Oded Balilty/AP Photo)

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)

Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)