Villa Romana de Pisões is the kind of archaeological site that rewards a little imagination. The Roman estate stood in open countryside west of Beja, and its surviving mosaics, water systems, and bath structures show how prosperous rural life could be in the ancient Alentejo. It is quieter and rougher around the edges than a city museum, but that is part of its appeal.
The site works best after you have seen Beja's castle and museum, because it moves the Roman story out into the farmland that sustained the city. Check access before going, since rural Portuguese archaeological sites can have limited hours and variable interpretation. With a car it is an easy detour; without one it is awkward enough to be worth planning deliberately.