Golarion is the default world for the Pathfinder RPG. It's the world where all of the Pathfinder Adventure Paths (APs), by default, take place. It's also the world where all the Pathfinder Society (PFS) adventures (aka slots or mods) take place.
I've found some nice videos that give a little background info about the world. A few give MORE than a little. The first two are quite nice and give the "ancient history" of the planet, at least as far as the humanoid race is concerned.
Great Golarion Intro Short - 4 mins long
Golarian Intro Video Longer - 6 mins long
Good intro, adds some details that the first doesn't add. 4 mins long
Skipping the beginning about the sodden lands would be good. I'd start about 50 second into this video.
...and Aboleths created humans. Sure they did...