and 15, all of whom had deep slashes across the sternum and broken rib cages indicating that their hearts may have been removed. According to National Geographic, if the analysis is correct, the discovery constitutes "the largest single mass child sacrifice event known in world history". The burial is dated at 1400-1450 A.D. Anthropologist Haagen Klaus speculates that Chimú might have turned to children when the sacrifice of adults was not enough to stop torrential rain and flooding caused by El Niño. In August 2019 the archaeological team working at this site revealed that the bodies of 227 victims, aged between four and 14, had been excavated, further establishing this as the largest-ever known example of child sacrifice. Architecture Differential architecture of palaces and monumental sites distinguished the rulers from the common people. At Chan Chan, there are ten large, walled enclosures called ciudadelas, or royal compounds, thought to be associated with the kings of Chimor. They are surrounded by adobe walls that are nine meters high, giving the ciudadela the appearance of a fortress. The bulk of the Chimú population (approximately 26,000 people) lived in barrios on the outer edge of the city. They consisted of many single-family domestic spaces with a kitchen, work space, domestic animals, and storage area. Ciudadelas frequently have U-shaped rooms that consist of three walls, a raised floor, and frequently, a courtyard, and there were often as many as 15 in one palace. In the early Chimú period, the U-shaped areas were found in strategic places for controlling the flow of supplies from storerooms, but it is unlikely that they served as storage areas. They are described as mnemonic devices for keeping track of the distribution of supplies. Over time, the frequency of the U-shaped structures increased, and the distribution of the structures changed, becoming more grouped, rather than dispersed, and occurring further away from access routes to resources. The architecture of the rural sites also supported the idea of a hierarchical social order. They have similar structural components, making them mini-ciudadelas with rural adapted administrative functions. Most of these sites have smaller walls, with many audiencias as the focal point of the structures. These would be used to restrict access to certain areas and are often found at strategic points. Chan Chan shows a lack of a unifying plan or a discernible pattern. The urban core contains six principal classes of architecture: Ten