The St. Peter's basilica is one of the most important churches of Cefalú diocese end it was elevated to the rank of Minor Basilica by Pope John Paul II with a decree of June 6, 1983. Its construction dates back to '500 first decade, it was completed in 1543, under Paolo III pontificate, and it was consecrated in 1548 by the bishop Mariano Manno from Sciacca. It was built next to the watchtower (a military structure which was once used as protection for a road), which served as bell tower until 1912. Besides the main gate, since its origin, the Basilica had another entrance on the right side, where a beautiful Catalan Gothic portal can still be seen.  The latin cross church, accessible through a majestic staircase, is divided in three naves supported by 14 polygonal base columns. Entering from the right side, a '700 sedan, decorated with gold inlays and fine paintings, is located in a theca; this sedan was once used by the pastors for the Corpus Domini procession; in this side are also located a 1650 marble baptismal font and 2 wooden statues of S. Rocco and S. Giovanni Battista.

San Pietro Collesano interior: The central naves is dominated by the Crucifix of the Providence, dated 1555, graven by Pernaci and painted by Antonello Sillaro. It is a great wooden artifact sided by two sculptures representing the Vergin and St. John, while on the back side is painted the Resurrection. On the sides of the triumphal arch stand out two statues representing St. Peter and St. Paul made by Li Volsi; The arch vault is decorated with frescos portraying scenes of Christ life. The barrel vault and the presbytery walls are painted with St. Peter and St. Paul stories, a 1624 artwork made by Gaspare Vazzano, also called the Gangi cripple. In the left nave can be found a marble statue representing the Presentazione di Maria al Tempio, made in 1546 by an unknown author; down the nave is located the chapel, with its Giovanni Giacomo Lo Varchi frescos, recently restored, and dedicated to the patron Maria SS. dei Miracoli. The painting of the patron, on canvas, comes from XV-XVI century but its author is unknown. In 2009 this painting was restored, returning to its former glory. Under the painting, in a wooden gold plated chest, are preserved the relic of martyrs S. Marco, Giacinto and Basilla. In the right nave is located the Santissimo Sacramento chapel adorned with an impressive marble ciborium, while at the chapel entrance is located marble tabernacle from 1489 made by Domenico Gagini. Also the wooden chorus bench, made by the Collesano carver Andrea Russo between 1570 and 1578, the pipe organo made by Antonino La Valle in 1627, and the recently restored choir must be mentioned for their artistic relevance.