Cambodia: An unknown people in the highlands of the country’s Cardamom Mountains buried their dead on rock ledges—in jars and coffins hand-hewn from logs. Researchers have conducted the first radiocarbon dating on 10 of these mysterious sites, and determined that these burial rites were practiced from at least A.D. 1395 to 1650. This period coincides with the decline of the lowland Kingdom of Angkor. In the lowlands, bodies were primarily cremated, so it is clear that this highland culture was very different from that of the Khmer people below.