You can spend an afternoon browsing the exhibits at National Archaeological Museum of Adria during your trip to Adria. While you're in the area, wander around the natural setting.
You can spend time studying the exhibits at Museo Regionale della Bonifica di Ca Vendramin in Taglio di Po. Wander the parks and beaches while you're in the area.
You can study the exhibits at Museo dei Grandi Fiumi, a museum with a story of its own, during your trip to Rovigo. Amble around the area's gardens or visit its monuments.