The Princes' Islands—a cluster of nine islands in the Sea of Marmara, known simply as "Adalar" in Turkish—are everything that Istanbul isn't: quiet, green, and car-less. They are primarily a relaxing getaway from the noise and traffic of the big city, though they can be quite crowded on weekends, particularly in summer. Restrictions on development and a ban on automobiles help maintain the charmingly old-fashioned and quiet atmosphere —transportation here is only by horse-drawn carriage or bicycle. There are few real "sights," per se; the main attraction is the laid-back ambience and natural beauty of the islands, which are hilly and mainly wooded, with a fresh breeze that is gently pine-scented. Thanks to frequent ferries from the mainland, an excursion to the islands makes a fun day trip, or a pleasant overnight getaway from the city.
The islands have served various purposes for the people of Istanbul over the years. Back in Byzantine times, religious undesirables and deposed members of the royal family sought refuge here, while during the Ottoman Empire, the islands likewise provided a convenient place to exile troublesome princes and other notables—hence the name. By the mid-19th century, well-heeled Istanbul businessmen had staked their claim and built many of the Victorian gingerbread–style houses that lend the islands their charm. The islands became especially popular as summer residences for Istanbul’s non-Muslim communities (Jews, Armenians, and Greeks), and were known for their cosmopolitan way of life. For several years in the 1930s, Büyükada, the largest of the islands, was the home of the exiled Leon Trotsky; the islands were considered to be safer than Istanbul, with its 35,000 hostile White Russian refugees.
Of the nine islands, four have regular ferry service, but only the two largest, Büyükada and Heybeliada, are of real interest to the general traveler, offering a variety of places to eat and stay and a few small beaches and other attractions. Two of the other inhabited islands are Kınalıada, long popular with the city's Armenians, and Burgazada, which has traditionally been more Greek. From the ferry you can see the larger two of the uninhabited islands, known in Greek and Turkish as the "pointy" Oxia/Sivri and the "flat" Plati/Yassı. Sivri's main claim to fame is that in the 19th and early 20th centuries Istanbul's stray dogs would be occasionally rounded up and dumped there, while Yassı was the site of the trial and execution of Prime Minister Adnan Menderes after a 1960 military coup.