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)

More than 6 billion people live in countries where serious levels of public sector corruption are fueling inequality and exploitation, according to Transparency International's 2015 index of perceived public sector corruption. The group's annual report measures perceptions of corruption due to the secrecy surrounding most corrupt dealings. Two thirds of the 168 countries assessed were identified as having a serious corruption problem. Somalia, which has been mired in conflict since civil war broke out in 1991, ranks bottom of the list. (Photo by Feisal Omar/Reuters)

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)

Actor George Clooney from the film “Ides Of March” arrives at the Hotel Excelsior during the 68th Venice Film Festival on August 31, 2011 in Venice, Italy. (Photo by Gareth Cattermole/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)

A man braces his umbrella while walking through the snow on February 13, 2014 in New York City. Heavy snow and high winds made for a hard morning commute in the city. (Photo by John Moore/Getty Images)

A motorcyclist dodges in the annual water-splashing festival to mark the New Year of the Dai minority in Menglian, Yunnan province April 13, 2015. (Photo by Wong Campion/Reuters)

A storm whips through a tented area occupied by Nepalese earthquake survivors as a mother grabs her infant child and runs to find shelter in Kathmandu, Nepal 23 May 2015. Nepalese, who lost their homes in earthquake and fear aftershocks, have been living in temporary shelter in open ground which they had to flee because of the heavy rain and powerful wind. (Photo by Narendra Shrestha/EPA)