Once you’ve installed History Tree, you can call it up and browse through your history file in a novel way. History Tree will display your browser history either in at-a-glance format where all your history pages are represented as thumbnails or as a tree structure—as seen here—where the path you took to get to each page is mapped out on a tree structure.
If you have a large browsing history, of course, it would be quite overwhelming to see it all at once. History Tree can create a display based on all your open tabs, all your open pages, selected tabs, or all closed tabs. Additionally, you can drill down by using a search box to pick through the pages.
History Tree is free and works wherever Firefox does.