This municipal house is really worth your attention. Its walls are covered in Baroque frescoes depicting Greco-Roman mythology.
Wikipedia https://de.wikipedia.org/wiki/Herzogshof_(Graz)
Official website http://www.graztourismus.at/en/see-and-do/sightseeing/sights/painted-house_sh-1231
Address Herrengasse 7, 8010 Graz, Austria
Coordinates 47°4'14.853" N 15°26'24.065" E