Ribeira de Seda originates in Serra de São Mamede and crosses the municipalities of Portalegre and Crato, entering Alter do Chão and then flowing into the Maranhão dam, in Avis.

Several medieval portals stand out along this street.

Location with picnic area and children's playground. Of note is an open-air exhibition area, an amphitheater and a traditional games field. Typical buildings, including a water scoop wheel, boilers, pergolas and viewpoints.

This viewpoint offers wonderful views over the natural landscape of the parish of Seda.

Urban fence built by King Afonso Henriques, in 1160, over traces of Roman occupation. It maintains three keeps, with the irregular termination of the structure being evident.

Built in 1617, it underwent modifications in the 18th century. On the main facade there are three windows, the sides being blind and the central one open, with a grille, topped by a panel of blue and white tiles depicting Saint Anthony. The pediment is cut out, with two small bell towers on the sides. The interior is of a nave, with the main altar in marble.

This Manor house was built in 1649 and remodeled in 1732. It has baroque outline with rectangular plan and two floors. On the main floor it stands out the seventeen hundreds decoration with paintings and the ceiling. The house is surrounded by a typical Portuguese garden with different interesting motifs, such as the houses for agricultural purposes, the watering systems, the waterwheel, the lakes and the tanks.

Roman bridge composed of six round arches supported on quadrangular pegs decorated at the base by two projecting moldings. Above the arches there are a raised cornice and guards with gargoyles. In one of the corners that close the main arch, there is a carved half-moon.

All that remains of the old castle is the pointed door and some sections of ruined wall, located around 400 meters above sea level. Initially built in the 13th century, the castle was heavily damaged in the 17th century.

In the heart of the town, in a large square, stands this imposing medieval castle, with a quadrangular plan and protected by cylindrical cubes, crowned with battlements, Gothic portals and a tall square keep. This, around 44 meters high, has a hall with a barrel-vaulted ceiling. At the entrance to the fortress, an armored marble tombstone inscribes the record of the castle's foundation, in 1359, by King Pedro I. At that time it was constituted as a defensive articulation with Estremoz, Fronteira, Évora Monte, Avis, Alter Pedroso, Marvão and Portalegre. King João I, Master of Avis, made Nuno Álvares Pereira …