The Basilica rises up an ancient destroyed parish church, and dates back to July 24, 1825 by the project of the architect Antonio Serra from Bologna (1783/1847). The temple, opened on February 5, 1838, was solemnly consecrated on July 1, 1855. The first document concerning the parish church is a gift deed of July 31, 1113. The maps of late XVIII century and of the beginning of the XIX century testify the pre-Romanesque style of the temple, that belongs to the first Christian monuments in Italy. The demolition of 1825 was therefore a serious offence to the history of art.
The neo-classic Basilica rises on the Square of the parish church, and has an atrium of eight Corinthian columns. It is accessed through a staircase. The fronton carries the inscription: Divo Marino Patrono et libertatis auctori Sen. P.Q. On the main entrance door there is the Republic coat of arms; the one on the right is a memorial stone with the inscription: “The General Arengo of the heads of family - legally congregated - restarted to exercise the ordinary sovereignty”.
On the right side of the Basilica of Saint Marinus is located the Small Church of Saint Peter. It can be accessed through the vestry and by a staircase in the bell tower. It dates back to the XVI century, but it was restored and made smaller in 1862. The apse, made by live rock, contains two niches carved into the rock. According to the popular tradition, the niches are Christian tombs and represents the beds of Saint Marinus and Saint Leo, to which the church-goers attribute miraculous faculties.