Next on my trip in Alentejo was a visit to the Cromlech of Almendres, one of the biggest megalithic structure in Europe.
It was a little hard to find, the road was really bad, and actually we got lost on our way and found another smaller structure somewhere in the opposite direction.
When we finally found it, it was a little disappointing: it is big, yes, it is very old, yes, but kinda nothing happens there, just a big pile of big rocks...no magic, no extraordinary feeling.. although it is very interesting to from where architecture started and go back the roots.
Anyway, I advise you to go visit them if you are on your way to Evora. They are relatively close to the main road (around 14 km) and if you follow the signs you willl have no problem in finding them.