1. The Mariana Trench — the deepest part of the ocean, at roughly 7 miles (11 kilometers) deep.
2. It is said that 94 percent of life on Earth is aquatic, however about two-thirds of all marine life remains unidentified. New species are being discovered all the time.
3. Oceans have lakes, and rivers, that exist underwater can you believe that ? But its true. According to NOAA ( National Oceanic and Atmospheric Association) this happens when seawater seeps through thick layers of salt, the salt dissolves and forms depressions in the seafloor. NOAA says that dissolved salt also makes the water in that area denser and this causes it to settle into the depressions. Brine pools are the names given to these underwater lakes and rivers and they have shorelines and even waves just like the lakes and rivers on land.