Um, I don't want to be a pedant here, but --

OK, I am being a pedant.

Stonehenge has 2 kinds of stones: the bluestone; only source Wales; and the outer circle of Sarsen stone, a very hard sandstone available not far away.

The older site with wooden post holes is Woodhenge, not far away.

If it didn't come up in the article, Stonehenge is NOT druidic in origin; it is much older, common wisdom to the contrary. People assumed it was for a longtime, until relatively modern analysis showed it to be much, much older.

This all from the recent book I read summarizing Stonehenge until quite recently.

One other theory I heard on a documentary, and probably still theoretical, is that Salisbury Plain is a central spot for many foot traffic routes from all over the isles. i.e., a meting place of some kind.

not only pre Anglo-Saxon invasion, but possibly pre-Briton as well.

End of soapbox.