A prehistoric necropolis yields clues to the ancient use of sound and its effect on human brain activity.

Researchers detected the presence of a strong double resonance frequency at 70Hz and 114Hz inside a 5,000-years-old mortuary temple on the Mediterranean island of Malta. The Ħal Saflieni Hypogeum is an underground complex created in the Neolithic (New Stone Age) period as a depository for bones and a shrine for ritual use. A chamber known as "The Oracle Room" has a fabled reputation for exceptional sound behavior.

During testing, a deep male voice tuned to these frequencies stimulated a resonance phenomenon throughout the hypogeum, creating bone-chilling effects............