You should definitely see - The Topkapı Palace

The Topkapı Palace is a palace in Istanbul (Constantinople), Turkey. Topkapı Sarayı in Turkish means the "Cannongate Palace". It was built in 1465. The palace was the administrative center of the Ottoman Empire. It was turned into a museum at the request of Turkey's firstPresident, Mustafa Kemal Atatürk in 1924. It was built on the acropolis, the site of the first settlement in Istanbul. The palace has an very good view of the Golden Horn, the Bosphorus and the Sea of Marmara. The palace is surrounded by 5km of walls. It has an area of 700,000 sq. m at the tip of the historical peninsula.