The Sanctuary of Monti-Sion is located 250 m above sea level. Access is through a road that was built by the inhabitants of Porreres in a single day, 14th January 1954, as a sign of popular devotion. There are seven 15th century Gothic pillars along the way, with portrayals of the seven joys and the seven sorrows of the Virgin Mary. At the top there is a cloister that is unique in Majorca: it has a pentagonal shape with galleries that are covered with round arches.
The oratory can be dated to the late 15th century, although the current building was refurbished at a later date. It is formed by a single nave with a rib vault. The altarpiece is in Neogothic style, with an image of the Virgin of Monti-sion made in marble, with a coat of arms at the bottom, probably from the Dusai family, one of the benefactors of the temple. The sacristy has a Virgin Mary that was purportedly made by Gabril Mòger and probably dates from the 15th-16th centuries.
The Monti-Sion Sanctuary was famous especially because it was used as one of the three schools of grammar of the island (the others being Santa Magdalena and Randa). It was the last study centre before access to the Estudi General, in Palma. Its grammar lecture room, from the late 16th century, is preserved. It has a gate with a flat arch with the coat of arms of Porreres flanked by the relief of an inkwell and a notebook with an inscription in Latin.