The Neoclassical Basilica of San Gaudenzio was designed by Pellegrino Tibaldi and built between 1577 and 1656 on the orders of the Emperor Charles V.

Its striking pinnacled dome, designed by Alessandro Antonelli, towers to a height of 121 metres, and was added to the main body of the church in 1888. The Bell tower (92 metres), designed by Benedetto Alfieri, was also a later addition to the church.

The Basilica is built on a Latin cross plan and has a single nave with side chapels, a transept and a deep presbytery. The chapels contain important  paintings by Gaudenzio Ferrari, Tanzio da Varallo, Moncalvo, Morazzone and Fiammenghino. The Basilica’s Scurolo (a sort of ground-level crypt) holds an urn with the remains of St Gaudentius, the first Bishop of the city.

The impressive Dome of San Gaudenzio was built using only local material, and although less well-known than the celebrated Mole Antonelliana in Turin (by the same architect), is an especially daring piece of architecture given its construction wholly in load-bearing brick and its masterly incorporation into a pre-existing building.

The Bell tower, set apart from the church, is built of terracotta and Baveno granite, and possesses the largest peal of bells using the Ambrosian system.