Santa Eulalia de Bóveda is a late Roman sanctuary from the 3rd century. It was dedicated to the goddess Cybele and was converted to the cult of Santa Eulalia. The building had two floors, although today only the lower floor or crypt remains, which is almost in its original form except for the central part of the vault, which was lost when the old Christian chapel that occupied the upper floor was demolished.

Prior to the Christian chapel, the first floor functioned as a Taurobolio. The taurobolio was a room for the sacrifice of a bull on the upper floor of the building, over the central part of the crypt and over the hole that allowed the animal's blood to fall into the pool on the lower floor. The belief in the healing properties of blood baptism made its practice very common in antiquity, especially in the 2nd and 3rd centuries. The Sanctuary of Cybele was designed for a possible repetition of the ritual in a short time and must have allowed for a large number of sacrifices at its most popular time. When the rite was banned with the adoption of Christianity, this first floor lost its original function and was transformed into a chapel, with the ground floor becoming a crypt. The crypt has a perfectly square floor plan and an exterior length of 12 m on each side. Its structure has two perimeter walls, an outer wall that serves to contain the earth that surrounds it on three sides, and an inner wall that supports the vault of the central room. The crypt opens to the outside through a façade with a small atrium that leads to the entrance door of the lower enclosure.

The interior of the crypt contains a marvellous collection of murals, the most important of those that survive in the whole of Hispania. The pictorial representation makes direct reference to the relationship that the birds and their songs had with the sanctuary and its functioning as an oracle. The live birds were hidden from the view of the devotees and their prophetic songs resounded over the paintings on the vault inside the crypt. These paintings are located in the vault and depict the sibyls in the form of birds and are in an excellent state of preservation. The ensemble includes partridges, pheasants, hens, peacocks (symbol of the goddess), doves, a goose and a duck, among stylised plant motifs representing the sacred tree of Attis, the pine tree and its fruit. The lower wall paintings disappeared when the sanctuary was Christianised and probably referred to the mysteries of the goddess.

The sculptural repertoire has little to do with classical Roman sculpture and could be more closely related to Visigothic art from later centuries, but it undoubtedly makes direct reference to the goddess who was the patron saint of the sanctuary, as well as to the rite that was practised. In the background and presiding over the ceremony is the "Black Stone", considered to be of celestial origin and considered to be an epiphany of the goddess Cybele. This stone is supported on a column and is associated with images in the atrium of ostriches perched on a stone on a slender column, as a zoomorphic personification of the goddess.