Once the user has identified a document of interest, navigation becomes a task of finding the appropriate location within a document. This may be a matter of searching for the occurrence of a string or of finding some structural component. Landmark tools are designed to allow the user to survey some aspect of the overall document. The Landmark tools are intended for use when when the entire document is not visible in the display window. The tools are dependent upon the availability of a scroll bar with a variable sized thumb. In CASCADE, thumb size is determined on a line basis. The mural allows the user to quickly locate potential areas of interest in the document and the thumb is used to quickly navigate to that point. Two Landmark tools are currently employed in CASCADE --Mural and Tilebars.