Photojournalist Jerry Redfern filmed this exploration of Cambodia's Phnom Kulen, a 15-mile-long plateau that was once the center of the vast Angkor Empire, which flourished between the ninth and fifteenth centuries A.D. Today, Phnom Kulen retains a central role in the spiritual life of the Khmer people. To read in-depth about the site, go to "Letter From Laos: Storied Landscape."