Do you know that

Area of sea: about 140 million square miles (362 million sq km), or nearly 71% of the Earth's surface.

Average Depth of sea: 12,200 feet (3,720 m).

Deepest point of sea: 36,198 feet (11,033 m) in the Mariana Trench in the western Pacific.

Mountains: The ocean ridges form a great mountain range, almost 40,000 miles (64,000 km) long, that weaves its way through all the major oceans. It is the largest single feature on Earth.

Highest Mountain: Mauna Kea, Hawaii, rises 33,474 feet (10,203 m) from its base on the ocean floor; only 13,680 feet (4,170 m) are above sea level.[source]