Do we live in Middle-earth?

[Gandalf_theGrey]

Right you are, Losthuniel.

* bows a greeting *

I've found a website that answers the question about the location of Valinor more eloquently than I:

Originally, the "fashion" of Middle-earth was the flat world of the mediaeval universe. Valinor (the equivalent of Heaven in that the "gods" dwelt there) was physically connected to the rest of the world and could be reached by ship. When Númenor sank "the fashion of the world was changed": the flat world was bent into a round one, with new lands also being created; and Valinor was removed "from the circles of the World", and could no longer be reached by ordinary physical means. The Elves alone were still allowed to make a one-way journey to Valinor along "the Straight Road". (An elven ship on such a journey would grow smaller and smaller with distance until if vanished rather than sinking over the horizon as a human ships do.)

The above quote comes from the following website:
http://www.daimi.aau.dk/~bouvin/tolk...ofnumenor.html

The same website also provides an answer to the main question of this thread.

At your Service,

Gandalf the Grey