Parking in Bologna

Hello,

We are coming from Venice to train station (Bologna centrale), taking car at Sixt at 2:30pm and we have probably 2-3 hours to visit in Bologna and maybe grab a quick snack and go to Riccione for 2 days.

Can you advise please how to plan this day. Where to park with rental car (our luggage - 2 carry ons, will be in the car. Is it safe?

And what we can see during 3 hours?

Thanks a lot.