What do most travelers associate Istanbul with? The Blue Mosque, Aya Sofia, Topkapi and Dolmabahçe palaces, the ancient reservoir Cisterna Basilica, the bustling Grand Bazaar, mountains of lukum and baklava in the stores on the central pedestrian street Istiklal and, of course, the majestic Bosphorus. This is usually the end of the standard program of visiting Istanbul. But not everyone knows about the Prince Islands in the Sea of Marmara, only fifteen kilometers from Istanbul.