Lording it over the electric green landscape, the scant ruins of the 12th-century Castello di Marmilla sit atop a perfectly pyramidal hill near the hamlet of Las Plassas, 3km southwest of Barumini. The castle was originally part of a defensive line that the medieval rulers of Arborea built on the frontier with the province of Cagliari.
To get to the castle from Las Plassas, follow the road for Tuili and you'll soon see a path on your left rising up the hill.