Poor communities in Germany?

I visited Germany a couple of years ago, and saw Berlin, Dresden, Nuremberg and Munich. While there I remember seeing on several occasions, outside Berlin and Dresden, these large communities of what appeared to be hundreds of one or two room shacks all built on the same location, not entirely dissimilar to an American trailer park. Recently, I was talking to my girlfriend and trying to describe these communities that I saw and I tried finding a picture to show her, but was unable to. Does anyone know what I am talking about? I cannot find any pictures to show what I am talking about and do not know the name of these places. They tended to be in suburbs outside of both Berlin and Dresden, although I have no memory of seeing them outside of Munich or Nuremberg.