Deep in Peru’s Acarí Valley lie the ruins of Tambo Viejo, an Inka provincial center where excavations have uncovered tasseled sacrificial llamas and brightly adorned guinea pigs. But save for a few seeds and some stored leaves, evidence of how the Inka used one of their most sacred plants in rituals remained elusive. Now, archaeologists have discovered coca leaves still stuck in the wool of some sacrificed llamas.
