A hierarchical tree visualizes the geographic structure of world countries, branching from continents into subregions and individual nations. The layout renders as a tidy tree using `d3.tree` and `hierarchy`, with horizontal links generated by `linkHorizontal` and SVG paths. Text labels appear at each node, with font size scaling by depth. The visualization supports pan and zoom interactions via `d3.zoom`, applied to a grouped SVG element. Data comes from a local `data.json` file, and the styling uses the Playfair Display font with text shadows for readability.