Below the unassuming streets of Canelli, four enormous wine houses excavated kilometres of underground galleries through the soft tufa, building cool, humid cellars where their sparkling wines could rest in bottle for years. The local nickname "Cattedrali Sotterranee" — Underground Cathedrals — captures the scale: vaulted brick aisles disappearing into the dark, lined with hundreds of thousands of bottles.
The four historic houses run regular tours and tastings, sometimes by appointment. The cathedrals were inscribed by UNESCO in 2014 as part of the Vineyard Landscape of Piedmont alongside the infernot of Monferrato Casalese. Reaching Canelli requires a short drive south from Asti, but it is one of the more atmospheric wine experiences in northern Italy.