The Acropolis of Civita 

 Alatri is known for the presence of the Acropolis that dates back to the pre-Romanesque age. It is surrounded by gigantic walls made of stone called polygonal walls. The precise period in which the Acropoli and its walls were built is unknown, but probably their realisation must be located between the Fourth and Third century BC. These walls can be admired still today thanks to their exceptional state of conservation. As legend would have it, they were built by an ancient population of giants that were able to place these enormous blocks of stone one above the other without the help of any kind of material to keep them together. This is why they are called cyclonic walls. The frame of walls that goes beyond the two metres of length, follows the tendency of the hill with a polygonal form. The Acropolis can be  accessed by the Porta Maggiore, situated on the southern part of the walls, with its enormous architrave that measures 4.5 metres in length and 2.68 in width, second in Europe to the Lion Gate in Mycenae. The staircase that leads to the door is part of the renovation made in the Nineteenth century. Near the Porta Maggiore there are inside the walls three big rectangular recesses, the profundity of which measures about 90 cm. These recesses are also called "the Sanctuaries" but their function is still unknown. There is also another front door, called Porta Minore, located on the northern part, that is far smaller than the Porta Maggiore: it measures 2,12 in length and 1,16 in width. Through the Porta Minore we can enter into an ascending corridor perfectly conserved. The Porta Minore is also called the "Porta dei Falli", due to the presence of three phallus carved into the stone as a symbol of fecundity. Along the slope situated under the northern part of the Acropolis, there can be found the remains of an ancient colonnade realised during the second half of the Second century BC thanks to the censor Lucio Betilieno Varo. The colonnade was necessary to connect the Acropolis to the Forum, precisely where today there is the Piazza Santa Maria Maggiore. During the Middle Age, the Acropolis lost, but only in part, its functions of holy area, it was fortified in order to defend the local population and it eventually became part of the residential zone. On the top of the Acropolis there is the Saint Paul's Cathedral, built on an ancient temple around the Tenth century. During the centuries it has been rebuilt numerous times and its current aspect dates back to the last reconstruction that took place around the Nineteenth century. On the inside there are the relics of San Sisto Papa, patron Saint of the city, and the ones of Sister Maria Cimatti. The main attraction of the Saint Paul's Cathedral is the Incarnated Host, a particular Eucharistic relic that miraculously transformed into human f lesh by the end of 1227. This miracle is also illustrated on the walls of the Cathedral.