Chavín de Huántar Acoustic Chambers
900–200 BCE
The ancient Peruvian temple complex of Chavín de Huántar contains a labyrinthine system of underground galleries that create disorienting acoustic effects — including sounds that appear to move through walls, echoes that distort the direction of sound, and resonance frequencies that match the call of the San Pedro cactus (a hallucinogenic plant used in Chavín rituals). Archaeoacoustic research has confirmed that the acoustic effects were deliberately engineered.