Wakayama Castle is the city's main landmark, rising from a broad park in the centre. The keep is a postwar reconstruction, but the stone walls, hilltop setting, and view over the city still make the stop worthwhile.
The castle belonged to the Kishu branch of the Tokugawa family, which gives the site more weight than its modest museum rooms suggest. Skip the small zoo in the grounds and spend your time on the keep, gates, and Momijidani garden instead.