Perched on the hill to the west of the city, the medieval village of Piazzo was founded in 1160 by the bishop of Vercelli, Uguccione, with the intention of building a safe residence to shelter from Vercelli when Ghibelline forces made it uneasy. Following the granting of privileges, Piazzo rapidly populated, becoming the centre of commerce and of the cultural and administrative development of the town. Over the following centuries, the residences of the great noble dynasties of Biella flourished at Piazzo: Scaglia Palace, Princes Dal Pozzo dalla Cisterna Palace, Gromo di Ternengo Palace, Lamarmora Palace, Ferrero Palace, and Gromo Losa di Prarolo Palace.

Today, the medieval village of Biella Piazzo can be reached from Biella Piano by a panoramic funicular railway.  The medieval urban layout, with its low arcades and narrow cobbled streets, and the extension of the town along the hillside, are still intact, thanks to the gradual transfer of the administrative centre to Piano in the 17th century. The walk along the cobbled lanes, among the medieval houses decorated in terracotta and ancient noble residences, is fascinating.  The central Cisterna Square, at the heart of the village, is lively and busy, especially in summer, thanks to the typical restaurants and bars housed under the arcades. There is a smaller one on the south side, overlooked by the 13th-century St James' Church and Gromo di Ternengo Palace.

Biella Piazzo offers a wealth of vantage points: you can look out from the bridge in Via Avogadro, from the De Genova public gardens and those of Ferrero Palace to admire the city, from Cucco Square for a glimpse of the surrounding hills, including the Burcina Park, recognisable in May thanks to the colourful blossoming of the rhododendron valley.