Situated in a large natural bay, between the islands of Tavolara and Milara, Olbia is famous as the "port of the Costa Smeralda".

The first settlements are dated to the Medium Neolithic Ages (approx. 4000 b.C), but the first important traces belong to the Bronze Ages and precisely to the Nuragic civilization (name taken from the Nuraghe, typical megalithic tower built by these inhabitants), which developed all over the island. Near Olbia there are 50 excavation sites with these traces from small villages to the megalithic sacred tomb pits such as Sacred Pit of Sa Testa, the Nuragic burial grounds of Su Monte and s'Abe and the nuraghe of Riu Mulinu a Cabu Abbas.

In Olbia, each civilization has left a sign of their passage: to those of the nuraghi, there are traces of the antique walls and an entire district of the Punic period, the rests of a Roman Aqueduct and Forum.

Monuments to visit: the Basilica of San Simplicio, built between XI and XII century, an important proof of the Pisa style Romanesque architecture; the Castle of Sa Paulazza, a Byzantine fortress, the Medieval Castle of Pedras, the Church of San Paolo Apostolo, was probably built in the Low Middle Ages but seriously damaged in the XVIII century; the Town Hall built in a Liberty and Neogothic style, Villa Tamponi with Neoclassic forms, the National Archeological Museum (Naval Museum) and the Theater of the Gulf.