The most extensive of the island's 7,000 discovered nuraghi, Su Nuraxi's significance merits its inclusion on the UNESCO World Heritage List. Concentric rings of thick stone walls conceal dark chambers and narrow passages in a central, beehive-shape tower. The excellent guided tour (which, depending on the nature of the group and language abilities of the guide, may be available in English) allows you to explore the interior. In the ruins of the surrounding village there are benches, ovens, wells, and other Bronze Age remnants.
The specific functions of individual nuraghi remain a mystery, largely because their construction predates written history. Though this particular type of construction is unique to Sardinia in Italy, similar buildings dating from the same era are found in other parts of the Mediterranean, such as Cyprus and the Balearic islands off Spain. All visits are accompanied by a local guide, start every 30 minutes, and last for approximately 50 minutes. The same ticket also allows entry to a museum and exhibition center in Barumini. If you're driving from SS131, don't be misled to other, lesser nuraghi—follow the signs all the way to Barumini.