Board Thread:Theories/@comment-26472215-20160222034906/@comment-27441457-20160222213540

We can be sure that the walls are located near to Europe given the clear European influence in the characters' names and the general look on the districts, but Germany is a bit too small for the walls themselves based off of the dimensions given in the anime. In my opinion, the walls could be located further east near Poland, Ukraine, Romania, etc. where there's a whole lot more elbow room. I hope Isayama gives some more hints in the future.

However, I'm 100% sure that the year 850 in the Attack on Titan timeline isn't the same as our world's 850 A.D. In my opinion, it would make more sense for the walls' timeline to be based off of some event in our own future. The Titans seem like some sort of biological weapon of mass destruction that would be created in a far future, with the events of Attack on Titan taking place in some future dark age.