A Domus de Janas - a ‘house of fairies’ - is usually an artificial cave dug into rocky blocks and used as prehistoric burial sites. La Rocca is also a Domus de Janas but was built into a boulder as big as a three-storey building, shaped firstly by nature and, more significantly, by man. It is thus considered as the ‘Domus de Janas cathedral’, perhaps being the largest on the island. La Rocca rises up on the edge of the Baldana valley, on the lip of the limestone plateau where Sedini, a village in the Anglona region, is located just a few kilometres from Castelsardo. The monument dominates the town from above, structured around it like a natural amphitheatre, between the hills of La Maglina and Lu Padru, reached by travelling along the main street of the town. The closer you get to the ‘house in the rock’, the more details about the twelve-metre-high boulder can be discovered. This magical location has spanned five millennia, from the 4th-3rd millennia BC (recent Neolithic) to the 20th century. The transformations throughout the centuries, especially in the Middle Ages, have rendered it part of the life of the village - it was a quarry that produced bricks, a prison, an animal shelter, shop and then a private home. Today, a series of environments from different eras can be visited that, carved into the living rock, integrate with each other via floors and masonry distributed throughout the three levels, currently housing the museum dedicated to Anglona’s ethnographic traditions. The 18th-century furniture, clothing, furnishings and looms recount the story of the agro-pastoral history and culture of the community of Sedini, as well as the archaeology, starting from the Neolithic necropolis, which is the oldest ‘layer’ of the fortress (3500-2700 BC), connected to the settlements that eventually rose up nearby, with the plateau of the town dotted with caves inhabited in prehistory: Li Conchi, Li Caadaggi and La Pilchina. Inside the domu are six hypogeic chambers - two and a half metres in length and one a half metres in width - that have been meticulously modelled, with two having been merged into a single room, with split levels connected to each other. On the lower level, the burials have remained as in the past. Here, there are also three rooms used perhaps to lay out the offerings. From here, a hatch allows you to go down even further to the deepest tomb, then used as a cellar. The chambers on the first and second floors were prisons in the Middle Ages, going on to be used for a number of functions as time passed, the last being private homes located on the first floor until the 19th century, and on the second until the mid-20th century. Within, time seems to have stopped. From La Rocca, the streets of the historic town can be explored, with its houses resting on limestone rocks and spread out around the Church of Sant’Andrea, in Gothic-Aragonese style (1517). Amongst the countryside sanctuaries, San Pancrazio stands out, being a building made of limestone and trachyte perched on a hill. Another prehistoric monument is the white Nuraghe Lu Padru, erected with limestone boulders. It takes its name from the homonymous hill, inside which there are the high chambers of the Fossa de la Loriga (or Grotta di Speluncas) embellished with stalactites and stalagmites.