Beylerbeyi is a "small" Istanbul summer palace overlooking the Bosphorus from its Asian shore.
Built on orders of the Ottoman Sultan Abdulaziz (1861-1876), it's a delightful, if ornate, imperial residence with a fountain in the main salon, the usual sumptuous chambers, Bohemian crystal chandeliers, Sèvres and Chinese vases, and pleasant gardens (closed Monday and Thursday; stay 1-2 hrs)
The palace was often used as a guest house for visiting royalty. Empress Eugénie of France, Shah Nasruddin of Persia, Grand Duke Nicholas of Russia and other worthies enjoyed its comforts.
Sultan Abdulhamid II was deposed by the Young Turks in 1909, and spent the last years of his life (1913-1918) under house arrest at Beylerbeyi. Much of the furniture in the palace was made by the sultan himself, who was an accomplished cabinet-maker.
Üsküdar and Beylerbeyi have many good waterfront restaurants just right for a pleasant lunch or afternoon snack during sightseeing.