The Calich is a coastal lagoon about 5km north of Alghero, separated from the sea by a narrow sandbar. It is a protected wetland and a significant birdwatching location — flamingos, herons, egrets, and various waders use the lagoon seasonally. The surrounding low scrubland is typical Sardinian macchia.
The lagoon is also the origin of Alghero's famous seafood restaurants along the SP42 road nearby, which serve fresh catch including grey mullet (muggine) and sea bass raised or caught in the lagoon waters. The combination of a short natural excursion and a good meal makes the Calich a worthwhile half-day from the old town.