App developer coboltForge has released TheWall, an Android app an app based on the Berlin Wall. The app shows you if you are inside the former East or West Berlin, in which occupying power sector you are, and how far you are away from the border.
It also offers information about the wall, including the location of pieces of the wall scattered around the world, plus information about historical monuments related to the wall.
Each of the four former sectors is shown in different colours, complete with information about points of interest (POI) in that sector. For each POI, there is a Wikipedia link and an image. Wall-related POIs are shown both for Berlin, and the rest of the world.
The app works on Android phones running version 1.6 or higher of the Android OS.