In 1826, there was a terrible flood when the waters of the Aniene river overflowed its banks, carrying away houses with the force of the water. As a result, Pope Gregory XVI ordered the river waters be diverted through a tunnel, creating a magnificent waterfall over a steep gorge, crashing down 120m to the bottom of the canyon, and known as the Cascata Grande (Great Waterfall). The architects of this used the old riverbed and the gorge, and the thickly wooded setting, full of caves, ravines and archaeological fragments, to create the park of Villa Gregoriana.
