Monte d'Accoddi is an archaeological site in northern Sardinia

Sardinia

Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...

, between Sassari

Sassari

Sassari is an Italian city. It is the second-largest city of Sardinia in terms of population with about 130,000 inhabitants, or about 300,000 including the greater metropolitan area...

 and Porto Torres

Porto Torres

Porto Torres is a comune and city in northern Sardinia, in the Province of Sassari.It is situated on the north coast about 25 km east of the Gorditanian promontory , and on the spacious bay of the Gulf of Asinara.-History:...

.

It is the site of a megalithic structure dated to around 2700=2000 BC and discovered in 1954.
The structure has a base of 27 m by 27 m and probably reached a height of 5.5 m. It culminated in a platform of about 12.5 m by 7.2 m, accessible via a ramp.
It has been variously described as an altar

Altar

An altar is any structure upon which offerings such as sacrifices are made for religious purposes. Altars are usually found at shrines, and they can be located in temples, churches and other places of worship...

, a temple

Temple

A temple is a structure reserved for religious or spiritual activities, such as prayer and sacrifice, or analogous rites. A templum constituted a sacred precinct as defined by a priest, or augur. It has the same root as the word "template," a plan in preparation of the building that was marked out...

 or a step pyramid

Step pyramid

Step pyramids are structures which characterized several cultures throughout history, in several locations throughout the world. These pyramids typically are large and made of several layers of stone...

.
It has been partially reconstructed during the 1980s.