Haigh Sophia is actually a bit taller than that.  They've got scaffolding up inside it at the moment, there are 26 flights of steps with ten steps per flight to get to the middle of the dome.  The place is huge.  A mate of mine bought a great book on Sinan which had a complete set of floor plans for most of the buildings he bought :)  I may well need to dig into that when I have some time and I've finished this.  We were only in Istanbul for five nights so I never got to visit half the places I would have liked to go to.