Underwater rivers of denser saltwater flow along the ocean floor — carrying sediment and nutrients thousands of miles.

Water covers more than 70% of Earth's surface.

The Pacific Ocean is deeper on average than other oceans.

There are underwater waterfalls caused by differences in water density.

The ocean contains dissolved gold — approximately 20 million tons — but in concentrations too low to extract profitably.

Some deep-sea fish like the viperfish have teeth so large they cannot close their mouths.

The deepest part of the ocean could submerge Mount Everest.

The Dead Sea is so salty that nothing larger than bacteria can survive in it, and swimmers float effortlessly.

The giant amphipod thrives in extreme ocean depths.