This example shows a static tree visualization of world countries, organized hierarchically by continent and subregion. The tree displays country names as text labels, with link paths connecting parent nodes to their children. The code constructs the tree layout using D3's `tree` and `hierarchy` functions, then renders horizontal links with `linkHorizontal` and text elements in SVG. Pan and zoom interactions are enabled through D3's `zoom` event handler, while the data is loaded from a local `data.json` file.