An aerial view of a strip of fire retardant is seen that kept a large part of Yarnell, Arizona (R) from being destroyed July 1, 2013. An elite squad of 19 Arizona firemen was killed in the worst US wildland firefighting tragedy in 80 years apparently outflanked and engulfed by wind-whipped flames in seconds, before some could scramble into cocoon-like personal shelters. [Photo/Agencies]