All about the Ocean | National Geographic Society

The ocean covers 70 percent of Earth ‘s surface. It contains about 1.35 billion cubic kilometers (324 million cubic miles) of water, which is about 97 percent of all the water on Earth. The ocean makes all life on Earth possible, and makes the planet appear blue when viewed from space. Earth is the only planet in our solar system that is definitely known to contain liquid water.

https://www.nationalgeographic.org/article/all-about-the-ocean/