the whole war period, was commonly remembered as "Palm Sunday bombing". For a long period of time this air raid shelter was left abandoned and in a heavy state of decay (same thing was for the air raid shelter "scuole de Amicis"), only recently has been restored and opened to the public. Air-raid shelter "scuole De Amicis" Situated under the 1900s junior school E. de Amicis: like many others air-raid shelters of the town, it was used during the world war II in order to protect the civilians from the several air-raids of the time. In the present days it is used as an exposition gallery. Artillery outpost of the Roman bridge n° SR414 (1873) An outpost used until the second world war composed with several military installations Castle of the Asinara Also known as the "Castellaccio" it is an ancient medieval castle in the island of the Asinara. In the present days it is used as a fire protection outpost by the Asinara national park administration. Spanish towers (1323–1720) Aragonese tower (1325) Tower of Abbacurrente (1571) Tower of the Finance (1525) Tower of Trabuccato (1609) Tower of Cala d'Oliva (1611) Tower of Cala d'Arena (1611) Asinara penitentiary complex (1885) Known as the "Italian Alcatraz", it became famous in Italy after a revolt happened during 2 October 1973. In the penitentiary of the Asinara has been detained the most dangerous criminals of the Sicilian Mafia, the Camorra, the Anonima sarda ant the Red Brigades. In more than one hundred years of activity the only prisoner who successfully escaped from the island penitentiary was the italian criminal Matteo Boe. During the WWI and the WWII it was used as an exile colony for thousands of POW and political prisoners. The penitentiary complex is composed by several sections located all around the island: Penitentiary section "Bunker of Cala d'Oliva" Penitentiary section of Cala d'Oliva Penitentiary section of Fornelli Penitentiary section of Santa Maria Penitentiary section of Tumbarino Penitentiary section of Campu Perdu Penitentiary section of Campo Faro Penitentiary section of Stretti Penitentiary section of Trabuccato Penitentiary section of Case Bianche Penitentiary section of Elighe Mannu Archaeological sites Nuraghes Nuraghe Biunisi Nuraghe Monte Elva Nuraghe Margone Nuraghe Nieddu "Turris Libisonis" Archaeological park Roman bridge of Rio Mannu Palace of the "Re Barbaro" and domus of Orpheus Baths of Maetzke Baths of Pallottino (III secolo d.C) Mosaics's Domus (I secolo d.C.) Other sites Necropolis