Built in the 13th century at the behest of King Afonso III, it is one of the largest and most emblematic monuments of mendicant Gothic architecture in Santarém. During the 17th century, it underwent several renovations that modified its form. Currently, the eight rows of tall Gothic columns adorned with frescoes and carved capitals stand out, with lighting provided by a rose window and several windows and slits. Inside, the Gothic tomb of the founding king's illegitimate daughter is a prominent feature.

It is located on the first floor of the Municipal Library building, which originally housed the palace of the Barons of Almeirim, a characteristic Ribatejo mansion remodeled in the 19th century. This Museum Centre presents an important artistic and bibliographic collection, highlighting collections of painting, furniture, decorative art and sculpture, in addition to an interesting and unusual bookstore. Collections from the Camões Library and a collection of contemporary art can also be seen.

The Open-Air Museum is the ideal place to learn about the history of the municipality of Campo Maior and its people, from prehistory to the present day, without forgetting its ongoing connection with Spain.

The castle was rebuilt by King Dinis in 1310 and underwent restoration work in the 18th century. Of the old fortification, situated atop a hill, only some sections of the wall and towers remain, in addition to the 17th-century fortifications, with escarpments, parapets, and ravelins, built during the Restoration War. The Church of Our Lady of Grace stands out, with its gable façade, framed straight lintel portal, and oculus. This castle is a characteristic example of the border fortresses of lowland regions, with a bastioned system determined by pyrotechnic artillery.

The Campo Maior swimming pool complex has one indoor and one outdoor pool.

Prehistoric archaeological site, where excavations uncovered megalithic monuments.

A museum space inaugurated in 2005 that promotes and preserves the history of olive growing. It shows the process of cultivating and harvesting olives, up to their transformation into olive oil.

The Portas da Vila, also known as Portas de Santa Maria, are one of the most characteristic monuments of Campo Maior, and also one of the main entrances to the town.

A 17th-century palace with proto-Baroque and Baroque architecture. It has a Baroque garden with a fountain and pavilion decorated with vegetal and shell-shaped stucco elements.

The building, designed by renowned architect Siza Vieira, houses Rui Nabeiro's project for the production and sale of regional wines. Adega Mayor offers guided tours, booked in advance, to showcase the entire winemaking process, provide details about the building, and offer wine tastings. At the end, visitors can purchase quality products at the Mayor shop.