St. Peter's church in Montorio was built on one of the peaks of the Janiculum Hill, also known as the Mountain of Gold for the color of the earth found there. According to a late legend, which today is considered to be apocryphal, this was the site of Peter's crucifixion.

In 1480, Ferdinand and Isabella, the King and Queen of Spain who owned the land here, gave orders to start the building of a church on the remains of a monastery that went back to the 9th century. Bramante's famous Tempietto was also commissioned in fulfillment of a vow taken at the birth of their first child.
The great architect adopted a central plan for this building, making clear references to Christian martyrdom and pagan temples dedicated to heroic mythological figures. Doric columns were used to conjure up images of ancient Rome and the figure of the hero. These columns were trade marks of Vitruvius, a renowned Roman architect.
In the original design, the little temple with its curved lines was supposed to be completed with a round cloister; however, the cloister was never built. Today, a Franciscan monastery has surrounded the little temple, thus creating a square courtyard instead.
The Tempietto is one of the few buildings designed by Bramante that is still intact. It demonstrates how well the architect assimilated the concepts and canons from classical architecture while never merely imitating ancient buildings. His building, just like all the ancient temples, inspires a sensation of perfect harmony.
Fontanone Gianicolo, the Janiculum fountain: The water comes from Trajan's ancient aqueduct and is called Aqua Paola after Pope Paul V who reopened it after more than 1000 years of not being used. The fountain was made at the beginning of the 17th century and part of the decoration is formed by columns coming from the old basilica of St. Peter's.