Il Parco fluviale del  NeraThe territory of the Nera River Park has a predominantly longitudinal, is crossed by the middle course – Black lower for about 20 kilometers and is characterized by a narrow valley dominated by high wooded hills. The points of interest are the Marmora falls at Terni and the Abbey of San Pietro in Valle Ferentillo
The Marmora falls is a waterfall flow-controlled, among the highest in Europe, relying on a total elevation of 165 m, divided into three jumps.
It is located about 7.5 km from Terni, in Umbria, near the end of the Nera Valley, the long valley carved by the river Nera.
The name is derived from the calcium salts present on the rocks that are similar to white marble.
The waters of the falls are intensively exploited for the production of electricity, in the central Galleto. This makes the cascade real does not constantly working, but for most of the time is reduced to the size of a stream. The basin of the lake Piediluco acts as a reservoir for the power plant, built in 1929, capable of producing electricity with a capacity of about 530 MW. To adjust the operation of the plant and to allow the vision at all times and in defined periods, the waterfall is operated at maximum capacity, a beep warns the opening of the gates of regulation, and within minutes the flow rate increases up to maximum value. Normally, the waterfall runs a couple of hours a day, with extended hours of operation during holidays. You log on to the best vantage points on payment of an entrance fee.
The Abbey of San Pietro in Valle Ferentillo is one of the oldest and Umbria is one of the few examples of Lombard architecture in the region. According to tradition it was built by Faroaldo II, Duke of Spoleto up to 728, in the early Christian forms, in honor of the holy hermits Lazarus and John, Syrian hermits, who lived for 40 years in a cave near the present church.
According to legend, St. Peter would have appeared in a dream to Faroaldo II, inviting him to build a church and a monastery in his honor, where he met a holy hermit named Lazzaro.1 He went hunting in the Nera Valley, came upon the holy hermit already observed in the vision. Around the small oratory was built so Lachiesa dedicated to St. Peter and the Monastery which adopted the Rule of St. Benedict. Faroaldo therein, renouncing the Duchy, he took the monastic habit and died in the concept of a saint in 728 and was buried in a beautiful sarcophagus of Asian type, which is still present inside the church. The church has a gabled façade, oculus and Renaissance portal, facing the old entrance from Spoleto. The interior has a single nave covered by trusses, is decorated with a cycle of frescoes with scenes from the Old and New Testament, which is one of the cornerstones of Umbrian painting of the twelfth century. The transept ends with three semicircular apses; the central one is preceded by a antecoro, according to the models of Ottonian architecture. The high altar, the result of arbitrary restorations of 1931, is composed of fragments of the iconostasis of the eighth century that was to adorn the Lombard church. The plate that serves as frontal, commissioned by the Duke of Spoleto Hilderic, is carved and signed by an “Ursus Magester.” In the north transept altar table is made up of two Roman sarcophagi stacked that, according to tradition, contains the remains of Saints Lazarus and John, while in the eastern pillar of the south transept is a walled Roman sarcophagus of the column type , which is considered the burial of Faroaldo II. The mighty bell four orders can be dated to the end of the century XI.Il monastic complex is privately owned and has been recently renovated and allocated to the receptivity as a period residence.