We visited the "Palazzo Ducale di Mantova", an impressive medieval construction with several courtyards, towers and gardens.
The highlight of the castle is "la camera degli sposi", a fresco-painted room with paintings of the rulers, their family and their dogs.
I made this sketch from the river side, where you can get a perspective of the oldest part of the Castle. The main entrance, toward the center of the city, is from the Renaissance period