Valnerina

Valnerina (the valley of that river) is a valley featured in Assassin's Creed: Brotherhood. The valley hosts a small city, where Leonardo's war machine, the new and improved Flying Machine (now equipped with a cannon), was being mass-produced by Cesare's army. After stealthily sneaking his way up to the fortress near the city, Ezio used the Flying Machine to destroy the factories making the machines.

Database Entry
''A valley formed by the Italian Nera in the mountains of Umbria, the Valnerina was known for its winding roads and steep narrow passes. It was a particularly challenging landscape to navigate.''