Some of its bluestones have acoustic properties Perhaps they were used as a prehistoric form of bells? Read the rest of the story with a link @ http://www.newser.com/story/183363/stonehenge-holds-a-sonic-secret.html [Perhaps a way of signaling it's alien builders?]
There has been a few studies of the acoustic properties of the structure. There is plenty of evidence the blue stone was used for it's reverberation properties. And the whole arrangement was designed to project sound down the main approach to the henge
Stonehenge: First residents from west Wales... Stonehenge: First residents from west Wales 2 Aug.`18 - Researchers have shown that cremated humans at Stonehenge were from the same region of Wales as the stones used in construction.
A recent study ( Olalde et al. 2018 ) found out about the genetic identity of the ancient Celts who built Megalithic tombs. It was British Neolithic farmers who were genetically similar to Neolithic Iberians, carrying Y haplogroups such as I2a and G2, which suggests that British Neolithic farmers had Iberian ancestry. The Neolithic farmer ancestry in Britain came from the Mediterranean rather than the Danubian route of farming expansion, which was derived from migrants who spread along the Atlantic coast. However, the spread of the Beaker people (R1b) to Britain from the continent around 2500 BC replaced 90% of Britain’s Neolithic gene pool within a few hundred years.
