It's a pretty nice place. There are quite a lot of cherry trees planted in the park. Some historical relics are on display in the castle. Not much, really. There's also a viewing platform. Going out for a day, spending time, taking pictures is quite suitable.
A beautiful park, as we understand it, is the central park of Osaka. There is a canal where you can go boating. There is also a palace and a museum where the history of Japan is told. In the palace, you can climb the observation tower.