The Indian Ocean is the third-largest of the world's five oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi) or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica depending on the definition in use. Along its core, the Indian Ocean has some large marginal or regional seas such as the Arabian Sea, Laccadive Sea, Bay of Bengal and Andaman Sea.