Pre-Columbian South American Music
Pre-Columbian South American music is loosely based around a pentatonic scale. Whether or not this scale deviates from the contemporary 12-equal pentatonic scale is up for debate, though there is much speculation and research indicating that the Natives did not strictly adhere to a single fixed-tuning of this pentatonic scale.
Music of El Dorado (audio examples)
Music from the Land of the Jaguar (audio and pictures)