Middle Earth is a world teeming with life and environments of all kinds. It is surrounded at its edge by the great World Sea, which separates it from the harsh and wintery mountain outworld of Jotunheim. In the world's center stands the great keep of Midgard, the human's last bastion of defense against the Jotun's constant attacks. It is built by the Gods, and stands next to the steep mountains which reach all the way up to Gudeheim.
This is the realm in which one is most likely to encounter all kinds of creatures, both animals, humans, monsters jotuns, gods, and all sorts of other life forms which originally belong in the other eight worlds.