More Ghostly dancing - get stoned to see them

Oh..the picture's supposed to be sound waves... and nothing to do with the above post on the effects of Sandalwood...

Another programme (again probably Horizon BBC) depicted structures like Stonehenge and other stone Druid burial mounds as being sound resonators. No need for the woofers and tweeters here, the architecture was the ampilfier.
They told the tale that the ancients would have celebrations at certain times of year. OK. And within these cave like buildings, they would drum and drum and meet their ancestors long time buried.
They also showed that sound can make dust move in the fashion of sound waves. Something that I was reminded of at a recent AOR seminar.
But they failed to make the connection between seeing their dear departed and the dust and smoke reacting to the sound waves.....must be ghosts why not?