Megalitico - Portugal
Portugal
Evora, Alentejo
Visited twice with olive harvest group.
From Wikipedia:
The Almendres Cromlech megalithic complex near Guadalupe, Évora, Portugal, is one of the earliest public monuments. It is the largest existing group of structured menhirs in the Iberian Peninsula, and one of the largest in Europe.
This megalithic monument originally consisted of more than one hundred monoliths, some of which have been taken away for other uses. A recent dig showed that the complex had undergone several building phases during the neolithic period (5000 - 4000 b.c.).
It was found rather late, in 1964.