The Pacific, greatest of oceans, has an area exceeding that of all dry land on the planet. Herman Melville called it "the tide-beating heart of earth." Covering more than a third of the planet's surface--as much as the Atlantic, Indian, and Arctic oceans combined--it's the largest geographical feature in the world. Its awesome 165,384,000 square km (up to 16,000 km wide and 11,000 km long) have an average depth of around 4,000 meters. Half the world's liquid water is stored here. You could drop the entire dry landmass of our planet into the Pacific and still have room for another continent the size of Asia. One theory claims the moon may have been flung from the Pacific while the world was still young.