Nera

The River Nera.

The River Nera was a tributary of the Tiber river and was located in Italy. During the early 16th century, Cesare Borgia had established facilities in the valley of the river which were used to produce large numbers of Flying Machines. They were subsequently destroyed by the Assassin Ezio Auditore da Firenze, who stole one of the flying machines and used it to destroy the factories.

Reference

• Assassin's Creed: Brotherhood