Waves

Waves are everywhere - perhaps one could say accurately, waves are everything. Ocean waves are caused by a variety of sources - the sun (which is the root cause of the others, really), wind, and the moon, via tides.

The now accepted theory about the moon is it was created some 500 Million years or so after the creation of Earth 1.0. A planet the size of Mars collided with Earth 1.0, utterly destroying itself and the young Earth, reforming eventually into a more massive Earth 2.0, with a new satellite, the moon.

When Earth 2.0 finally cooled enough for water to form - and it took a while, for, veritably, it was Hell on Earth for millions of years - the tides were present from the start, and massive due to the proximity of the moon (much closer). For millions and millions of years, massive tides, hundreds of feet high, swept over the Earth, churning up everything. The theory now goes that it was this churning which was key in the development of life on Earth 2.0 (along with water, of course), as it broke up bigger rocks and mixed nutrients - such as iron - into the water, and thus to spread across the globe. These elements make us up, make everything up, and thus, life on Earth exists because of the moon. A theory!

Interesting tangent: If the moon were to magically disappear, all the water on the globe would instantly snap to a solar tidal pattern - which exists today, but is far weaker than lunar tides. This snap back would the biggest wave ever to exist on Earth, and would make an eternal legend out of some lucky surfer.