A real golden hall? In Stockholm? Yes, that exists! And I can tell you, it really is impressive when you're there for the first time! All you have to do is to go to Stadshuset. And book a guided tour. For approximately 45 minutes, a guide shows you this magnificent building. You'll see for example the hall where the Nobel Prize banquet takes place every year. The beautifully painted ceiling of some other halls. And then your guide will bring you to Gyllene salen, the mighty "Golden hall". It is huge and golden. And beautiful. The mosaic has many details and motifs of Stockholm and some of them will be explained. You should definitely see it when in Stockholm!
For further information about the tour, check out the website.