If you take a Bosphorus tour, you’ll pass many lavish and intriguing buildings, but the most opulent of them all, surely has to be the 600m long Dolmabahçe Sarayı (Dolmabahce Palace). It took 13 years to build and was completed in 1856, and served as the administrative center of the Ottoman Empire until 1922.
The palace was commissioned by Sultan Abdülmecid (who decided there should be a more European palace than Topkapi) and designed by Armenian architect Karabet Balian and his son Nikoğos Balian. (read Balyan family on wikipedia). It is an ostentatious blend architectural styles including Baroque, Rococo, Neoclassical and modern Ottoman, dripping in luxury.