KMZ is a file extension for a placemark file used by Google Earth. KMZ stands for Keyhole Markup language Zipped. It is a compressed version of a KML (Keyhole Markup Language) file. Keyhole was the founding company of the Earth Viewer software that Google Earth was built upon.
KMZ files can contain placemarks featuring a custom name; the latitudinal and longitudinal coordinates for the location, and 3D model data. KMZ files can be opened by Google Earth, or unzipped with a compression utility, such as WinZip on Windows, MacZip for Macintosh users, and Zip and UnZip for UNIX systems.