This funerary basilica was located next to the Roman road connecting Mértola to Beja. This important monument was partially excavated in the late 19th century, and several funerary inscriptions were recovered from it, now housed in the National Archaeological Museum in Lisbon. Currently, it houses a museum where the foundations and floors of the former church are preserved. This museum contains inscribed stelae, which constitute the most important collection of Early Christian tombstones found in Portugal.

The canals on the Guadiana River were used to capture fish. The last traps of this type are in the municipality of Mértola, which have been discontinued, diverting fish to easier-to-catch locations.

The Clock Tower was likely built in the late 16th or early 17th century, as part of the reorganization of the Praça do Município urban area. This building was erected near a group of buildings representing political, administrative, judicial, and economic power. Reusing an old city wall tower, it began to mark the boundary of Praça do Município and became one of Mértola's emblematic elements. In 1896, the original clock was replaced by a more recent one that continues to keep time in Vila Velha to this day.

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.

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.