exterior of the skull pagoda at the killing fields of choeung ek in against the blue sky. historical sights of phnom penh

architecture asia asian blue bone buddhism buddhist building cambodia cambodian choeung death exterior extermination famous field genocide grave historic historical history holocaust horror human kampuchea khmer killing landmark mass mausoleum memorial monument national outdoors outside pagoda penh phnom religion remains rouge skull sky stupa tower tragedy travel verdant victim violence