A recent study by researchers from the University of Helsinki revealed the unique acoustic properties of prehistoric rock art sites in Finland's Lake District. The study found that these sites provided ancient hunter-gatherers with a multisensory experience due to their special acoustic properties, where reality sounded doubled. The researchers theorize that ancient humans in these areas created a kind of prehistoric surround sound that produced an auditory mirror image of the reality they painted onto the rocks. The study suggests that these sites were likely visited for ceremonial purposes, as they were considered sacred places and seats of rituals.