The detail and freshness of the facade are extraordinary. Try to visit the Duomo around sunset, as the light causes the church to take on a pinky/coral tone.
The palace was the seat of the city’s government and housed the courts, the prison, and the grain market. It is not open to the general public but you can admire its exterior.
Over the years, these caves have been used for everything from storing wine and food to providing shelter from bombs in World War Two.