Architizer looks at the basic places where Game of Thrones filmed in order to figure out what places were inspirations for King's Landing, Astapor, "The North", etc.
Le Mag thinks various cities or courts stand for specific places in Europe.
If you can't remember what the places look like, see the various
title sequence videos where the cities emerge like automated toys.
Qarth
The armillary sphere that acts as the sun over this sequence is itself taken from Renaissance designs, such as the amazing one in the Museo Galileo.
Intro scene armillary sphere
Museo Galileo armillary sphere