A castle of Romanesque and Gothic architecture, with quadrangular towers. The keep stands on the steepest slope. Of the medieval gates, only the Misericórdia Gate, overlooking the Guadiana River, remains. The old citadel, as well as important sections of the wall that enclosed the town, remain. Archaeological work in the castle's citadel has uncovered a Moorish quarter from the 12th and 13th centuries and several Roman structures from the 4th century. The Arab ceramics found are on display in the Mértola museum.

The Roman House was the first museum section of the Mértola Museum to open in 1989. It is located in the basement of the City Hall building. During renovation work, important archaeological remains corresponding to the foundations of a Roman house (today it serves as the main building) emerged. In addition to the walls of the old building, where part of the house's impluvium stands out, period architectural elements, funerary epigraphy, ceramics, and metalwork are on display. Each section has a permanent exhibition related to its theme.

On the northern slope of the Castle Hill, the possible Roman city forum creates an artificial platform, supporting the imposing monumental complex of the city of Myrtilis. This entire platform, leaning against the wall, rested on a solid underground gallery approximately 30 meters long and 6 meters high. In Late Antiquity, in the 5th and 6th centuries, lavish religious buildings were erected here; among them, a possible Episcopal Palace and a baptistery, of which significant fragments of a beautiful set of polychrome mosaics remain. During the Islamic period, during the 12th and 13th centuries, this entire area was occupied by …

On a steeply sloping area below the castle lies the old mosque, converted into a Christian church in the 13th century, with a Manueline-Mudejar façade featuring battlements and spires. It is the only one that still retains the volume and some decorative elements of the Arab temple that preceded it, notably the "T" layout, the presence of the mihrab and the compartment in the "qibla" (mosque wall) facing Mecca, the existence of five naves from the old mosque, the statuary, doors, and remains of the mihrab.

Created in 1995, the Guadiana Natural Park, which encompasses the municipalities of Mértola and Serpa, boasts flora, fauna, morphology, and, most importantly, landscape features of great beauty and interest. The middle stretch of the Guadiana Valley, between Pulo do Lobo and the mouth of the Vascão River, with its enclosed valleys and numerous tributaries, boasts above-average beauty. Notable are the presence of wild boar, little bustard, great bustard, otter, black stork, griffon vulture, wild olive trees, and mastic trees.

Straddling the municipalities of Mértola and Serpa, this waterfall is of rare beauty. It's approximately 14 meters high, in a place of rich geological heritage, where the river flows with a tremendous roar between two cliffs. A narrow rocky strait strangles the river so much that it overflows, forming a waterfall. The imposing landscape lends a unique beauty to this place, steeped in legend and history. During floods, the drop in water level is reduced, allowing several species to travel upstream to spawn.

The former Misericórdia Church of Mértola houses the first municipal museum of sacred art. This space, known as Porta da Ribeira, presents a unique collection of images and liturgical artefacts from hermitages and chapels of popular worship. Here, the different nuances of humanity's relationship with various references to the sacred are reconstructed, with the exhibition of sacred art from the 14th to 18th centuries, liturgical artefacts, including chalices and processional crosses, and painted tablets.

The Islamic Art Center opened in 2001 and represents the culmination of many years of work not only in archaeological interventions but also in the treatment and study of materials from the Islamic period. The collection, dating from the 9th to 13th centuries, comprises architectural elements, funerary epigraphy, ceramics, metals (copper and copper alloys, iron, and lead), worked bone (including artifacts directly related to weaving and glass objects).

A core part of the old defensive system on the Minho border. This former war zone rises on the banks of the Minho River and offers beautiful views of the leisure park and the thermal baths.

This route is designed for the leisure and well-being of the local population. Along the way, information panels are installed about the region's flora and fauna. The route begins at Pedra Furada, with access to Porta de Salvaterra, and continues towards Valença.