The secret of Finland's sacred cave, the Devil's Church, has been solved

A new study was conducted by archaeologist Riitta Rainio from the University of Helsinki and cultural studies researcher Elina Hytönen-Ng from the University of Eastern Finland on the Pirunkirkko, commonly known as the Devil's Church, located in Koli National Park in eastern Finland. The study investigated why the church was used in past shamanic beliefs.

The Devil's Church contains a corridor-like cave that is 34 meters long. People with shamanic beliefs in the past saw the cave as a region for connecting with the spirit world. Researchers Rainio and Hytönen-Ng focused on the acoustics of the cave, exploring its attributed mystical significance.

Acoustic measurements made in the corridor-like back part of the Devil's Church revealed that the cave has an acoustic resonance that amplifies and prolongs sounds at certain frequencies. This resonance suggests that the church was used in the past for healing rituals and drumming sessions.

It was discovered that Kinolainen, a renowned sage in the area, used the cave to heal his patients and organized rituals to communicate with the Devil. Rainio noted that these rituals generally involved loud shouting, stamping, and firing.

The cave's flat-walled sections produce a tone at 231 Hz. This tone makes sounds more powerful and prolonged. The sounds produced during rituals are strengthened by the cave's resonance, creating a mystical atmosphere. This is thought to have had an impact on people.

The research was published in the Open Archaeology journal.