The hills and coastline of Quartu Sant'Elena are home to 38 Nuragic settlements, the most beautiful of which is the Nuraghe Diana, dating from the middle of the 2nd millennium BC between the Late Bronze and Early Iron Ages and built to guard the Nuragic port. The Nuraghe Diana complex is unique, as the wall enclosing the inner courtyard was designed and built at the same time as the tower toppoed with a tholos false dome and the other two smaller connected towers. This modus operandi makes it unique among nuraghi that were expanded over time and only later were the other buildings annexed to the central tower. The construction technique is also an enigma, revealing unusual architectural and stylistic skills, a quest for beauty and a challenge to the laws of physics. In some places the upper stones are larger than the lower ones and the entrance follows the construction technique of a dolmen with a lintel and cyclopean sides, reminiscent of the entrance to the beautiful Giants' Tomb of is Concias in the countryside of Quartucciu. Excavations and tunnels can be seen around the nuraghe, not by archaeologists or grave robbers, but by treasure hunters looking for the treasure of the Saracen pirate Giacomo Mugahid, who was said to have buried it within these walls before leaving the island in the hope of returning to recover it and reunite with his wife. He never returned and it has never been known whether a treasure was actually found. However, the legend has survived, passed down through the grapevine, of the woman's spirit wandering within the walls of the nuraghe, guarding the hiding place and scanning the sea in the vain expectation of spotting the privateer's sailing ship on the waters of the Golfo degli Angeli (‘Gulf of Angels’). In memory of his love, the beach overlooked by the nuraghe was named Capitana.
The Diana is not only the inspiration for legends of pirates and treasure, but also a witness to bloody battles between privateers. The promontory at its foot is perhaps not by chance called is Mortorius, a sinister name in spite of its beauty. The thousands of years of history, of which the Nuraghe Diana can rightly boast, extend as far as the modern era. During the Second World War, it was once again a sentry on the sea, this time protecting the forts protecting against sea and air attacks camouflaged in the ruins of an old tuna fishery. At that time only the main tower of the nuraghe emerged from the hill, which was reinforced to build a sentry box. In the 1950s, after the end of the war, excavations began that brought to light a trilobate nuragic complex with a unique architecture created by the ancient architects, which the touch of modern history has not altered.