PERU: The culture that inhabited the Supe Valley between 3000 and 2000 B.C. is often considered the first city-building civilization in the Americas, having established urban centers with monumental pyramids and circular plazas. A recent project has determined that the location and orientation of these buildings was influenced by annual astronomical events—especially the moonrise’s southernmost position on the horizon—which coincided with cyclical changes such as the arrival of the rainy season, the beginning of winter, or the start of the planting season.