In a March, 2013 article published in Popular Archaeology, monumental structures were built to manipulate sound for sensory and mind effects, revealed in recent research.
The article explains how archaeologists studied a 6,000-year-old stone structure complex known as the Hal Saflieni Hypogeum on the island of Malta, and discovered that the interior spaces produce interesting effects.
The article goes on to describe how low voices within its walls create eerie, reverberating echoes, and a sound made or words spoken in certain places can be clearly heard throughout all of its three levels.
Also revealed are some more interesting findings:
“The findings indicated that at 110 Hz the patterns of activity over the prefrontal cortex abruptly shifted, resulting in a relative deactivation of the language center and a temporary shifting from left to right-sided dominance related to emotional processing and creativity.”
Read related article (links to a similar version from Ancient Knowledge)