this plugin is exactly, what I am looking for.
Unfortunately, no map is showing and when I checked the apache2 error.log, I found the following message:
> include(include_map.php): failed to open stream: No such file or directory in ../wp-content/plugins/nextgen-gallery-geo/plugin.php on line 15,
The include_map.php is missing in version 0.5.
I tried to use the file from version 0.42, but this also didn't work.