The Anghelu Ruju Hypogeic Necropolis, discovered in 1903, is located in the countryside of Alghero. The tombs are classified into two distinct types: -Well-type tombs (earlier), characterized by irregular floor plans. -Corridor-type tombs (later), typically arranged in a T-shape or radial pattern. The architectural features of these tombs are often elaborated with elements inspired by domestic structures of the living, such as steps, pillars, cornices, false lintels, doors, and windows. Artifacts recovered from the site are associated with the Ozieri Culture (4200–3400 BCE), indicating the necropolis's earliest usage. Many tombs were later reused throughout the Chalcolithic period (3600–2100 BCE). The Domus de Janas were sealed externally with stone slabs and have revealed collective burials of individuals predominantly laid in a supine position.