KML, or 'Keyhole Markup Language', is an XML grammar and file format for modeling and storing geographic features such as points, lines, images, polygons, and models for display in Google Earth, Google Maps and other applications. You can use KML to share places and information with other users of these applications. You can find example KML files on the KML Gallery and Google Earth Community site that describe interesting features and places.
A KML file is processed by Google Earth in a similar way that HTML and XML files are processed by web browsers. Like HTML, KML has a tag-based structure with names and attributes used for specific display purposes. Thus, Google Earth acts as browsers of KML files. Learn more (English Only).