the Italian region of the Lazio , with c. 27,900 inhabitants. A part of the traditional region of Ciociaria , it is famous for its megalithic acropolis . Panorama of Alatri. Contents [] 1 History 2 Main sights 2.1 Ancient remains 2.2 Other 3 Subdivisions 3.1 Rioni 3.2 Frazioni 4 Sister cities