The largest ocean in the world is the Pacific Ocean. Covering an area of approximately 63 million square miles (over 165 million square kilometers), it extends from the Arctic Ocean in the north to the Southern Ocean in the south and reaches the coasts of Asia and Australia to the west, and Africa and the Americas to the east. The Pacific Ocean is not only vast but also deep, containing the Mariana Trench, which is the deepest known point in the world's oceans. Its size and diversity of marine life make it a critical part of the Earth's ecosystem and climate.