The Velino river, flowing through the Ubrian highlands that surround the city of Rieti, about sixty miles (one hundred kilometers) north of Rome, feeds a wetland that is thought to bring illness (probably malaria).
To remove that threat to the city of Rieti, in 271 BCE, the Roman consul Manlius Curius Dentatus orders the construction of a canal (the Curiano Trench) to divert the stagnant waters into the natural cliff at Marmore.
From there, the water had fallen into the Nera river below.
However, that solution creates a different problem: when the Velino river is in flood stage, its water flows through the Nera toward the city of Interamna Nahars (modern Terni), threatening its population.
The one hundred and sixty-five meter waterfall, known today as the Cascata delle Marmore, is one of the tallest in Europe and the tallest man-made waterfall in the world.
Of its three sections, the top one is the tallest, at eighty-three meters (two hundred and seventy-two feet).
Its source is today only a portion of the waters of the river Velino (the rest of the river now flows into a hydroelectric power plant).
After flowing through Piediluco lake near the community of Marmore, the waters pour into the valley below, formed by the river Nera.
In modern times, its flow is turned on and off according to a published schedule, to satisfy the needs of tourists and the power company alike.
Tourists try to be there the moment the gates are opened to see the powerful rush of water.
