sentences:  The municipality is also known for the archeological sites of Serbissi (together with Osini, a big nuraghe built on the top of a mountain and on the top of a natural cave, originally used to store food) and Is Tostoinus.Gairo's territory is also famous for its natural beauties.Perd'e Liana, for instance, is one of the most important and evocative morphological conformations in Sardinia.