While most of the streets in Verona are paved with asphalt there are still a many streets, and piazzas, that are paved with various types of other materials. The most dangerous are these large blocks which have many seams, missing chunks, and are uneven; also very, very slippery in the rain:
These small cobbles are good to ride on but you have to be on the alert for ones that are missing, I think tourists take them as souvenirs. And in some spots the blocks meet the cobbles:
There are a few places that have river rock and there is usually a strip to ride your bike. The strip can be a granite or marble. Riding on wet marble is like riding on ice.
I typically ride on each of these surfaces to get to the ride starts. I've had a few close calls.....