The thing that is so striking about Istanbul is that it's a mixture of Europe and Asia, of Islam and Christianity....no where is it more pronounced in St. Sophia the ancient basilica built by Constantine the Great in the 4th century and reconstructed by Justinian in the 6th century. When the Ottoman Empire ruled it was converted into a mosque and now it's a museum/tourist site.
During many of the renovations, mosaic panels were discovered. One in particular is quite spectacular. It is the Virgin Mary between Justinian, who is presenting St. Hagia Sophia and Constantine presenting a model of his new city.
The next photo is a marble jar (standing nearly 5 feet tall) made from one single slab of marble from the Peragamon area of Turkey. The jar was presented by Murad III who was the Sultan ruler from 1574-1595. It is quite an extraordinary piece and there's two of them.