Gök is the color of the sky (or sky itself), the name refers to blue tiles that have mostly gone but adorned the entrance of the 1276 mosque.
The Torumtay türbe houses a number of graves, among them that of Torumtay, a ruler of that age. It is to the right, the small building facing the mosque. Another Türbe is attached to that mosque (the one with the pointed roof).
The shot was taken from high up on Kale hill (420 mm of lens did the trick).