Between 1600 BC and the 6th century BC in a very peculiar time in Sardinia, it sees the development of the Nuragic (in english should be read Nuraghik) age.

The most representative monumets of this age are the buildings and the architeture of villages which are called Nuraghi (Nuragi) or Nuragic villages.

Nuraghi are built with square stone bloks layed ona on top of the other to form a tower shaped like an truncated cone. Nuraghi can be formed by just one tower or even by up to five towers connected by walls. Inside many rooms at different levels are connected by stairs on the walls.

This is Wikipedia’s article:

The Nuraghe /nu’rage/ is the main archaeological megalithic monument of Sardinia. It is typically a truncated cone tower, in the shape of a beehive, built with huge square blocks of stone, and usually located in a panoramic position. The monument has no foundations, and stands only due to the weight of stones, which may weigh as much as several tons. Some Nuraghes are more than 20 metres in height. Today, there are more than 8,000 Nuraghes in Sardinia, though it has been estimated that once the number was more than 30,000. The nuraghes are concentrated most in the north-west and south-central parts of the island. Another kind of Nuraghe has a corridor or a system of corridors. Some authors are reluctant to place these in the same category as tholos Nuraghe, as there are too many relevant differences, and prefer talking about “Nuragic village”. Nuraghes appeared on the island in an undetermined epoch (not earlier than 6th millennium BC). Some elements have been dated 3500 BC, but it is supposed that most of them were built from the middle of the Bronze Age (18th-15th centuries BC) to the Late Bronze Age, though many were in continuous use until Rome entered Sardinia (2nd century BC). The uncertain date of the Nuraghes is a constant feature of Sardinian chronologies. Even though, according to Massimo Pallottino, a scholar of Sardinian prehistory and Etruscologist, the Nuragic civilization produced the most advanced and monumental architecture of the period in the western Mediterranean, including the region of Magna Graecia, of the existing 8000 only a few have as yet been scientifically excavated. Interest in Sardinian archaeology has been minimal, except for the black market trade in bronze statues. The use or meaning of the nuraghe has not been clearly identified: whether a religious temple, or a dwelling, a military stronghold, the house of the chief of the village, the place for the meeting of the wise men or the governors. It could have been as well a combination of all or some of these items. Some of the nuraghi are, however, in strategic locations from which important passages could be easily controlled. 

Undoubtedly nuraghes had a meaningful symbolic content, at least recalling wealth or power, or maybe the establishment of a village (eventually in the dignity of a State-village). Recent theories are oriented to consider that Sardinian villages might have been federated (very likely they were self-governed) and that the building of these monuments could depend on a prior planned distribution of the territory. Nuragic dwellers had developed particular skills in metallurgy, trading for bronze in many areas of the Mediterranean and being consequently a well known people.