In its long history, Istanbul / Constantinople / Byzantium has served as the capital city of the Roman Empire (330–395 AD), the East Roman (Byzantine) Empire (395–1453), and the Ottoman Empire (1453–1922). The (Islamic) Ottoman Empire succeeded the (Christian) Byzantine Empire in controlling much of Southeastern Europe, the Middle East and North Africa. Istanbul has been for many centuries the place where the Eastern and Western worlds meet. The historic areas of Istanbul were added to the UNESCO World Heritage List in 1985.
Hagia Sophia ("Divine Wisdom"), built by Emperor Justinian in 532-537 AD, was the largest church in the world for 1000 years. It is considered one of the greatest and most beautiful buildings in history. It became a mosque under the Ottomans when they conquered Constantinople in 1453.
The monumental Blue Mosque (Sultan Ahmed Mosque) was built in 1609-1619. Its architect was trying to compete against the Byzantine architecture of the nearby Hagia Sophia Cathedral, which it resembles eventually in some ways. The interior design though is classically Islamic.
The walls of the Blue Mosque are covered by beautiful tile, but blue is just one of the colors…
The Topkapı Palace on a hill overlooking the Bosphorus was the official and primary residence of the Ottoman Sultans up to 1853. This Chamber of Petitions is where the Sultan would sit on his canopied throne, surrounded by gold and jewels, and personally receive the Viziers and officials.
The Imperial Harem of more than 400 rooms within the palace contains the private apartments of the sultan, the concubines and wives of the sultan, as well as the eunuchs who served them.