Casa Grande Ruins National Monument, located in Coolidge, Arizona, preserves the remnants of an ancient Hohokam community that flourished between 1200 and 1450 CE. The centerpiece is the "Great House" (Casa Grande), a four-story structure built from caliche—a natural cement-like material. This impressive building, constructed around 1350, showcases the Hohokam's advanced architectural skills and their deep understanding of astronomy. Notably, the structure's walls align with the cardinal directions, and a circular hole in the upper west wall allows sunlight to illuminate a specific spot during the summer solstice.