The science of archaeoacoustics reveals that some prehistoric barrows were potentially used for frightening and mysterious rites. Surrounded by decomposing bodies, initiates may have been exposed to infrasound - inaudibly low frequencies known to affect brainwaves, producing hallucinations and altered states of consciousness. Some megalithic structures also have audible resonances that produce a musical interval known as the ‘perfect fourth’ – a ratio of 4:3 that is also found in the proportions of their stone chambers. Elsewhere, the huge stones of a cove were positioned to produce a mysterious echo, perhaps used as an oracle. What secret rituals did our Neolithic ancestors perform at these sacred ancient archaeological sites? [[{"type":"media","view_mode":"media_large","fid":"59286","attributes":{"alt":"West Kennet Long Barrow (Image © Steve Marshall)","class":"media-image","height":"161","style":"width: 610px; height: 161px;","typeof":"foaf:Image","width":"610"}}]]
