The first parish church of the Valley, St. Siro dates back to the 6th-7th century, but it was rebuilt in the 12th century. The church presents itself remarkably without a front, substituted by the rock wall where the building rests; the main entrance is therefore placed on the side, with the marvellous portal sculptured with zoomorphic and phytomorphic motifs, below which are positioned two statues representing a lion and a lamb. The inside is divided into three naves, ending in as many apses jutting out impressively over the underlying cliff. Below the presbytery there is an ancient crypt from the Longobard age, where one can notice interesting Roman waste materials and traces of frescoes. The opposite wall from the presbytery is occupied by a staircase dug directly on the rock, while the lateral walls of the church display frescoes from the 14th and 15th centuries, among which stands out the beautiful “Virgin on the throne with the Child”.