As I work for a GIS company much of what you find here is map-related. Actual maps can be found at mapintosh.de At the moment it does not look like much but that's only a start.
A Stolperstein (literally: “stumbling stone”, metaphorically a “stumbling block”) is a 10 cm edge length concrete cube bearing a brass plate remembering a victim of Nazi terror. It is embedded into the pavement at the person's last chosen address.
The links in this section do not send you to a download page but to pages in this wiki with details on why I recommend the software (which of course have links to actually get the software).