The ancient stone temple complex at Chavín de Huántar has attracted much interest in recent years, including the possible ritual use of psychedelics at the site (see Mike Jay's article "Enter the Jaguar", available as a free download from the Darklore website, and also the image above which apparently shows an individual holding a psychedelic San Pedro cactus). Another fascinating aspect of the site, with its labyrinthine internal architecture (and which Mike mentioned in passing in his article as being possibly used in conjunction with the psychedelics), is the place's strange acoustics, and how they may have been used by Chavin's residents. Researcher José Luis Cruzado Coronel has written a fascinating article for The Appendix describing investigations of this topic over time, including the excavation at the site of a number of pututus (shell trumpets/horns):
In the 1970s, Peruvian archaeologist Luis Lumbreras and teams discovered a terraced canal running beneath Chavín’s Circular Plaza staircase that created a tremendous sound effect when water was poured through. This was the first documented archaeological consideration of sound at Chavín... Conservation limits such physical testing, so questions of the site’s ancient sound environment were put to rest for decades with the 1976 publication of an article that estimated hydraulic sound effects related to the monument’s extensive subterranean canal system and interior architecture. Now, armed with non-invasive research tools, my team’s on-site archaeoacoustics fieldwork has introduced new technologies to probe the elemental and potentially subversive sonic environment of this proposed oracular center.
...The architectural acoustic link between the Lanzón Gallery ducts and the site-excavated sound-producing instruments is a rare gem of archaeological correspondence that’s difficult to dismiss as coincidence. First, Chavín’s architecture is thoroughly channeled with ducts of different shapes and sizes. Therefore, unique structures of a particular size and placement among these ubiquitous forms suggest planned construction: design.
Second, the location of these tuned sound conduits — between the consequential stone monolith and the exclusive plaza setting — would be ritually significant, and it’s riddled with other links to shell horns. In this apparent ceremonial locus, pututus are depicted, as if performed by figures in procession, on stone reliefs lining the north-western wall of the Circular Plaza, just a few meters away from where the Strombus-projecting ducts open onto overhead walls. The plaza floor was crafted with two inlays of fossilized sea snails on its paving stones, spiraled animals that appear like cross-sectioned pututus. A few meters south, a plausible pututu storage location exists: in the Caracolas Gallery where Rick’s team unearthed these instruments, they were deposited as if they had been hung along its walls. This constellation of factors provides strong support for the idea of ancient ceremony enlivened by the sound of these horns.
You can find out more about the team's research on this topic at the project website at Stanford University, which has some cool content including video of a pututu being played over the top of imagery of this enigmatic site.