"Guayabo National Monument Costa Rica’s largest archaeological find was uncovered in the late 1800s as laborers cleared land to plant coffee. The 540-acre site, believed to have once been home to 10,000 people, was abandoned before the Spaniards arrived. Its ancient residents left behind artifacts and relics that attest to major advances in civil engineering, notably aqueducts, paved streets, and sophisticated drainage systems, achievements that have led to the area’s designation as an International Historic Civil Engineering Landmark. Hiring a guide is recommended for understanding the site’s importance; it features several impressive monoliths, fascinating petroglyphs, and stone carvings that depict the jaguars and alligators that were central to indigenous belief systems. By Travesías"