Example KML export link from this website for map ID 5
Each map has a corresponding KML-Feed which can be accessed directly, e.g.
http://www.[your-domain].com/maps/export/kml/5
You can use the generated KML-file to display the included markers or layers directly in Google Earth which is available for Windows, Mac OS X and Linux. Please note that you need an internet connection to display your maps correctly as the marker icons and popup-images are loaded from the source you provided them.
As an alternative, you can also use the links above to display your maps in Google Maps via the feature “My Places“. To add your maps to Google Maps My Places, please proceed as follows: