Bologna's big venue for outdoor events
Not the world's most beautiful park, but it has an arena and hosts circuses, festivals, rock concerts etc as well as the annual Communist shindig, La Festa dell'Unità (Bologna, naturally, hosts the largest one in Italy). It also has a large car park, on Via Stalingrado.
Bus 25 from the train station or Piazza Maggiore
Car park website
+39 051 325757