 These were located farther inland in fortified towns (pucara), and chullpa burial and ceremonial towers still remain.Although the Aymaras were based, and prospered in, the harsh altiplano conditions they also controlled lands on eastern slopes of the Andes that were more suited for food production – colonies were also established in lowland temperate and semitropical areas in order to grow adequate food stocks to sustain their populations.This type of society organization has been called the vertical archipelago.