This church museum houses the usual array of religious artefacts, but differentiates itself with its Labirinto di Porsenna, a series of tunnels (not for the claustrophobic) dating from Etruscan times that formed part of Chiusi’s water-supply system. Guided tours of the labyrinth (in Italian or English, depending on the crowd), leave at 10am, 10.45am, 11.30am, 12.15pm, 2.30pm, 3.15pm, 4pm and 4.45pm in high season, less regularly at other times.
The museum occupies a building next to the duomo, extensively rebuilt in the late 19th century and decorated inside with unusual frescoes resembling medieval mosaics.
