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Also....
Q. How large is the world?
We don't know the final size of the playable world, only the size of the starting continent.
The starting continent is approximate 256km x 128km.
It is estimated that it will take 48-hours of non-stop walking (at 1.5m/s) to walk one edge to the other, if the world is flat with no obstructions. Add in the mechanics required for resting, changes in the terrain (forests, rivers, mountains), etc., and this estimate will increase. (Borrowed from the Wiki)