stylistic:style_transfer, structural:summarization
Islands

There are two main groups of islands in the Sea of Marmara. To the north lie the Princes' Islands, an archipelago made up of the inhabited islands of Kınaliada, Burgazada, Heybeliada, Büyükada and Sedef Adası and several uninhabited islands including Sivriada, Yassıada, Kaşıkadası and Tavşanadası. The inhabited islands are readily accessible by ferry from both the European and Asian shores of İstanbul and the entire archipelago forms part of the conurbation.

To the south lie the Marmara Islands, an archipelago made up of the eponymous Marmara Island and three other inhabited islands – Avşa, Paşalimanı and Ekinlik – as well as of seventeen largely uninhabited islands including the prison island of Imralı whose most famous prisoner, since 1999, has been the PKK leader Abdullah Öcalan. These islands lie within Balıkesir province and are most readily accessible from Tekirdağ in Thrace or Erdek on the southern shore of the Sea of Marmara. In high summer additional ferries travel to Avşa and Marmara Islands from the centre of İstanbul to facilitate a growing tourist trade.

There are also a few individual islands elsewhere in the Sea of Marmara, such as Koç Adası, off Tuzla, which is privately owned by the Koç family of industrialists.