The ruins of the Castle of Sopramonte can be accessed from Prato Sesia. The tower, the small church, the ruins of the castle, and the splendid view that can be admired from the small courtyard or from the extreme northern point of the hill give the place something magical. Just at the top, on the right, there is a tower (11th-12th century) of considerable size: about twenty meters high, with an almost square base, without battlements, much altered over time and featuring a small balcony. About a hundred meters from the tower are the ruins of the Castle of Sopramonte: entirely built of river pebbles woven in a herringbone pattern bound with mortar, it had at least three towers, the oldest of which is the one near the church of Santa Maria. The square-planned base of this large tower is still visible today, while to the east of the tower opens a circular cistern. In 1363, Galeazzo Visconti had the fortified places where the English troops had taken refuge demolished, and on that occasion, the castle was partially destroyed. The small church of the castle, rebuilt in Baroque style and in good condition, is dedicated to the Nativity of the Virgin and houses a fresco from the 15th century depicting Saint Sebastian and a Bishop Saint. Serravalle Sesia is dominated by the majestic ruins of the ancient Castle of Vintebbio, which around the 1200s was part of a chain of fortifications defending the territory between Gattinara and Roccapietra. The exact date of construction of the castle is unknown, but it is likely that its oldest nucleus was built around 750-800, probably on the ruins of a Roman castrum. Thanks to the bishops of Vercelli, it was incorporated into the defense of the territory in the complex of fortifications that once stretched along the Sesia River, but in 1559 it was destroyed by the Valsesians. Some very thick perimeter walls remain of the castle, as well as a southern square-plan protruding tower with a wolf-toothed frieze, some narrow slits, well-preserved bifora windows in the eastern wall, and a portion of the entrance. The castle can be reached with a simple 15-minute walk through the undergrowth from the village of Serravalle Sesia by following trail 702.