I believe that The Retreat is the same cabin we see at the end of The Incredible Hulk, except with a few modifications. When I first seen the dent that Skye uncovered in the wall, it immediately reminded me of that cabin. Bruce Banner could have possibly made contact with shield and Fury had the place built. Whether it was to contain him if he got out of control, or if it were a place for Banner to learn to control his anger, I don't know. I suppose it is also possible that Banner built it then Fury added some modifications to it so it would be more like a safe house, like it is now.

I believe that The Retreat is the same cabin we see at the end of The Incredible Hulk, except with a few modifications. When I first saw the dent that Skye uncovered in the wall, it immediately reminded me of that cabin. Bruce Banner could have possibly made contact with SHIELD and Fury had the place built. Whether it was to contain him if he got out of control, or if it were a place for Banner to learn to control his anger, I don't know. I suppose it is also possible that Banner built it then Fury added some modifications to it so it would be more like a safe house, like it is now.