Its construction began during the 12th century, with new elements being later added, particularly during the 14th and 16th centuries, to make up its present day structure, a mixture of Romanesque, Gothic and Baroque. The towers, which comprise three sections and a pyramid-shaped top, are located on the upper part. The main entrance has two pairs of pillars with archivolts and a plain tympanum. It gives access to the Sacred Christ Chapel, of rectangular design and Baroque style. It was constructed between the 17th and 18th centuries.
Of particular interest is the 18th-century altarpiece, especially the image of the Sacred Christ of Barba Dourada (Golden Beard), a Gothic sculpture alleged to have been carved by Nicodemus in the 14th century and a central element in a number of legends. One such legend tells that, after stealing the figure, the robbers were forced to throw it overboard as they fled, in order to calm the storm that had resulted from their crime. The figure of Christ was later recovered by a fisherman. Another legend affirms that the hair and nails of the figure grow. Legends apart, what is true, as any visitor will be able to verify, is that a Festival and a Pilgrimage to the Sacred Christ are held every Easter Sunday outside the church. One of the most exciting moments in this celebration is when the procession reaches the church and the "Danza das Areas" (Dance of Sands) begins, an ancestral dance the roots of which have been traced by historians back to the 17th and 18th centuries.
In the Main Chapel we can admire the tabernacle (Baroque), the image of Nuestra Señora de las Arenas (Our Lady of the Sands) (Renaissance), patron saint of the parish, and the chapel's beautiful window (Romanesque). The Gothic "Purísima" (Holy Virgin) Chapel, which dates back to the 15th century, has a ribbed vault. Access is through a pointed arch. The central nave forms part, together with the main chapel, of the original core of the church. Its outstanding elements are its Gothic arches and half columns, and the figure of Santiago Peregrino (Saint James the Pilgrim). The arch over the entrance to the baptistery and its ribbed vault are both Gothic. It contains the tombs of two recognised benefactors of this temple. Its construction dates back to between 1225 and 1250, making it the oldest chapel of those annexed to the central nave. In the past it was called the Chapel of Santa Lucía. The 16th century chapel of Our Lady of Carmen, of Plateresque style, shows evident influences of the New Cloister at the Santiago de Compostela Cathedral (the vault and the archbishop's coat of arms).
It has an altarpiece that displays the emblem of the Order of the Carmelites. Santa María occupies an importance place in the mysticism of the Road to Santiago, to which it belongs and to which it gives continuity beyond the boundaries of Compostela. After visiting the tomb of the Apostle, the pilgrims continued their route on to Fisterra, to pay homage to the Sacred Christ facing the Atlantic. To attend to the faithful, in the late 16th century the Hospital de Peregrinos de Nuestra Señora del Rosario (Pilgrim's Hospital of Our Lady of Rosario) was founded right in front of the church's main façade. During the Holy Year, the so-called Holy Door is used, an ornately decorated portal on which the coats of arms of the Feijóo and the Recamán families can be identified.