Marble is an application that displays a view of the earth. It is both a valuable application in its own right, but also an example program that shows how you can use the Marble widgets in your own applications. The Marble application makes use of the following classes and widgets: 1. MarbleWidget, the main widget in any application using the Marble framework. This widget displays a view of the earth or any other globe, depending on which dataset is used. The user can navigate the globe using either a control widget, e.g. the MarbleNavigator, or the mouse. 2. MarbleModel, the data storage class that holds the data that is visualized in the MarbleWidget. The MarbleModel is created internally and can be accessed using the model() method. These two classes provide the core of the classes that comprise the Marble framework. You can use only them and get a very capable application.