Siren bridge. Originally built in 1842 over the corner of what are now Via Senato and Corso di Porta Venezia, they were moved here when the canal was covered up. (Boo-hoo! Let's reopen the canals!)
This gives me the opportunity to mention that, in general, Italy is not equipped for those in wheelchairs. At all. You might have a corner, or two, with handicapped ramps, then the subsequent ones don't, or, if they do, have been created just after a traffic light or sign pole that squeezes access. Buildings, even those from just before and after the war, either don't have elevators, or, if they do, the elevators don't go to the ground floor (those crazy architects...thinking more about 'gentility' of style than practicality). There's almost always two, three or ten stairs to go up before an elevator can be reached. Then there's the thorny question of historic buildings. Should, or even CAN, the historic structure be cut and modified to add elevators? It's a question without an easy answer, but here at the Acquarium, it already has been solved. (Before someone writes in the comments about politically-correct language, I personally think this is one of the instances where it has gone overboard. "Disabled" sounds like a machine whose functioning has been destroyed. Much better to de-stigmatize the word already in use. That's my two cents' worth.)
vedovelle" (little widows, because they are constantly "weeping") throughout the park and the city. The water is not just safe to drink, it's also good. For those of you new to town, you don't have to break your back bending down to drink out of the gush from the little dragon's mouth. Look on the top of his head. If there's a little hole (and there should be one), stop up the dragon's mouth, and the water spurts up out of his head.