My personal highlight was the Hagia Sophia. Seeing that great architecture which was for about 1000 years the centre of the Christian world was a great experience.
Also very impressing was the Blue Mosque and the Aya Kiryaki Church.
And the quarter around the Akbıyık Fountain had a very nice atmosphere and great cafes with good views.
Enjoy your time there!
Of course, I know Hagia Sophia and the Blue Mosque are beautiful, I've been there many times. but I think I haven't seen Aya Kiryaki and Akbıyık fountain. Our next stop is Aya Kiryaki Church! and than Akbıyık Fountain! :)
I also like the ideas visit of Hagia Sophia and Blue Mosque, I used to take pictures of them but I think I can't find them. So its an opportunity to go and visit again :)
Thank you very much!