The oceans hold 97% of all the water in the world.

As the sun warms the surface, water evaporates. It vaporises into the sky until it cools and condenses into towering clouds. And they generate huge storms.

The spin of the Earth deflects these storms north and south into cooler latitudes.

As they travel across the sea, storm-driven winds create huge swells.

When the swells reach shallower water, they rise into gigantic waves.

In it lifetime, a large storm can release energy that is the equivalent of 10,000 nuclear bombs.

These are the seasonal seas. And when they warm in spring, they can suddenly explode with life.

Mobula rays have gathered in Mexico's Sea of Cortez in vast numbers.

Why do they leap? Is it to tell others that they are here? No-one knows.

They feed mostly at night, for that is when vast swarms of plankton rise from the depths.