Keyhole Markup Language (KML) is an XML notation for expressing geographic annotation and visualization within Internet-based, two-dimensional maps and three-dimensional Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. It was created by Keyhole, Inc, which was acquired by Google in 2004. KML is an international standard of the Open Geospatial Consortium. Google Earth was the first program able to view and graphically edit KML files. Other projects such as Marble have also started to develop KML support.