Well Greek mythology has been popular to the media, and has many derivatives, as it keeps inspiring artists to create new stories.

It is popular as a fantasy setting these days, as also Tolkien's universe.

But the actual Greek mythology wasn't supposed to be a fantasy setting. Most of it was about giving explanations to various matters that couldn't be answered somehow else, and as a form of early 'science'. I say that, because most of what is included in the divinities of ancient Greek folklore, are personified natural forces or objects. For example Hesiod's creation story says that first Gaia (Earth) appeared, and that she gave birth to Uranus (Sky), and that then they got married and gave birth to Potamos (River), Oceanos (Ocean), Oros (Mountain)...

Interesting to know is that the Greek language is such, that most of each words will either be masculine or feminine. So Sky is masculine, and Earth is feminine, and that way its easy to come up with the rest of the details for attributing personalities to them.

For me, the part of Hesiod I wrote about, is about is seen as a form of primative natural history: It basically tells that the Sky came to existence by Earth (I assume Sky is the Atmosphere, as you know, without Earth's mass for there to be substantial gravity there would be no atmosphere), and that then the Earth and Atmosphere had intercourse (meaning the ingredients of these two were mixed and reacted with each other,) resulting to the creation of the Oceans, Rivers, etc.