We’ve taken some military maps from Wikimedia Commons to produce a KML layer. A KML file is a file that contains geographic annotation and visualisation for earth viewing software. Within the map are 4 layers – some of which might obscure other layers, and so you can turn these off and on, or, in Google Earth, scale a layer’s opacity.
Instructions for opening in Google Earth: If you haven’t already, download Google Earth to your computer, and open the KML file. You can use your cursor to move around the globe and in many cases zoom down to street level.