Java is the heartland of Indonesia with more than 130 million people inhabiting an area as big as Greece. Formed mostly as the result of volcanic eruptions, Java is the 13th largest island in the world and the fifth largest in Indonesia. A chain of volcanic mountains forms an east–west spine along the island. Java is divided into four provinces, West Java, Central Java, East Java, and Banten, and two special regions, Jakarta and Yogyakarta.