Kumamoto Castle
Kumamoto castle has a long history dated back to the early 1600s, with many of the walls originals from the time of the warring samurai. While the buildings themselves are reconstructions, the complex is extensive with a lot to see, with many of the interiors open to the public.
Access
The castle of a 30 minute walk from Kumamoto station or you can take a bus of the A-Line tram (details here). After visiting the castle Suizenji Park is a short walk away.