Silva,it’s a neolithic site,part of the Stonehenge complex of SH,Durrington and Woodhenge. Some archaeologists have suggested Durrington was for the rites of the living, Woodhenge a site for rites of the newly dead,and Stonehenge was for thespirits of the blessed ancestors. Woodhenge has a midsummer alignment. Recent excavation has also confirmed that there were stones amidst the posts,including a three sided cove made of sarsen. Some bluestone fragments have recently been found in post holes.
I would personally like to see the concrete markers replaced with wooden posts,to give a better feel of how it might have appeared.