Aviano Castle is located just outside the center of the modern city and is an important historical work. Of very ancient origin, it was built around the 10th century on a hill that allowed it to be able to control the surrounding territory. After a violent siege that nearly destroyed it, it came to the Serenissima, which allowed it to be rebuilt in 1432. It was also used in medieval times as a military training site and to control trade movements in the area. Today, parts of the keep and the city walls that once enabled the defense of the manor remain standing. Within the walls, some dwellings and also the church of St. Mary and Juliana can be visited.