Clearly visible from many localities of the Val di Non, Castel Valer stands out for its imposing mass of grey stone, its countless windows with two-coloured shutters and its architectural features, which present two distinctive elements: the octagonal plan of the keep and the subdivision of the complex into two fully autonomous sections: Castel di Sopra and Castel di Sotto, along with the chapel of Saint Valerius and the surrounding rural buildings.

The castle can be reached via two unpaved roads: the first climbs from Tassullo through orchards, while the second descends from Sanzenone through farmland once owned by the Spaur family, now planted with apple trees. The two roads converge at an ancient stone bridge that gives access to the castle.

Outside the castle, in the northern garden, stands the chapel of Saint Valerius, dating back to the 15th century.

The pitched roof is topped by a small wooden bell tower.
The interior consists of two adjacent rectangular rooms with cross vaults: the nave and the chancel, separated by a pointed arch.
The chancel features an exceptionally well-preserved fresco decoration with a complex iconographic programme, attributed to the brothers Giovanni and Battista Baschenis – well-known painters of Bergamasque origin – and an unknown Tyrolean painter.

Upon entering the castle, one has the impression of stepping into a small medieval village, the result of the juxtaposition of 14th-century buildings with the second defensive wall.

The structures unfold in a circular layout, following the contours of the terrain and creating a series of distinct spaces.
To the right of the entrance, on the second floor of a 14th-century forebuilding, there is a large loggia overlooking the villages of Tassullo and Rallo, offering a magnificent view of the entire Upper Anaunia and its mountains.

Castel di Sopra is the highest structure in the castle complex. It was the residence of the Obervaler branch of the Spaur family — still flourishing in Austria — who, for centuries, lived a life completely independent from the inhabitants of Castel di Sotto.

The upper courtyard is enclosed to the west by a building bearing the Obervaler Spaur coat of arms on its façade, depicted in relief on a metal plate.