Arzachena is a quiet Gallura market town about 25km north of Olbia, set inland from the Costa Smeralda among granite hills and cork oaks. Most visitors come for what surrounds it rather than the town itself: the countryside here holds one of the densest concentrations of Nuragic prehistoric monuments in Sardinia, the legacy of the Bronze Age civilisation that flourished on the island from roughly 1800 to 900 BC.
Within a short drive lie multiple Giants' Tombs — long galleried collective graves fronted by tall carved steles — including the dramatic Coddu Vecchiu and Li Loghi, along with the unusual circular necropolis of Li Muri and several nuraghi, the round stone towers that are the island's most recognisable ancient structures. The town's Museo Civico provides useful context before you head out to the sites, and a single ticket often covers several of the monuments.
The town has a modest historical centre and a good weekly market, but its real value is as a hub. It sits at the junction of roads leading both down to the resorts of the Costa Smeralda and inland to the quieter heart of Gallura, which makes it easy to combine a morning of prehistory with an afternoon on the coast. There are simple trattorias serving Gallurese cooking — suppa cuata, roast suckling pig, sheep's-milk cheeses — if you want to eat where the prices haven't been set by the yacht crowd a few kilometres away.
If you are basing yourself in Olbia, Arzachena is an easy half-day or full-day trip by car. Public transport exists but is infrequent, and the monuments are spread across the countryside, so a car makes the difference between seeing one site and seeing five.