Old postcards telling the history of Graz? You can get your fill of them online at grazmuseum.at. Or visit the cultural history museum of the city of Graz and take a look at the well-known permanent exhibitions: Go to "360 degrees" or dive into the "Schloßberg Utopia" - more Graz is not possible, it is a Museum of Life in Graz.
From bathhouse to art house: in 1904 the octagonal building was still a bathhouse, later a Samadhi bath (a very special wellness experience where you float in salty water in the dark) and today a place where you can experience unusual perceptions with all the senses of your own body: the highlight is still the Samadhi bath.
Admittedly, not quite in Graz, but we simply can't leave Arnie out here if he already has his own museum during his lifetime. Arnold Schwarzenegger's birthplace in Thal near Graz is supported by himself (which doesn't really surprise us) and shows exhibits from his career from a boy born and bred in Styria to his life as Terminator and US governor.
The Augarten in Graz is home to the architecturally exciting Children's Museum of Graz. Outside wow and inside wow: exciting exhibitions and theatre events in the Knopftheater await children from three years of age and their families inside. And what's always on Saturdays at two? The hands-on workshops for handicrafts and building.