This visualization displays a hierarchical tree of world countries, organized by region and subregion, using a horizontal dendrogram layout. The tree structure is rendered with SVG, showing parent-child relationships through curved link paths and text labels that decrease in font size with depth. The code uses D3 v5’s `tree()`, `hierarchy()`, and `linkHorizontal()` to compute and draw the layout, with `d3.zoom()` enabling pan and zoom interactions. Data comes from a local `data.json` file containing nested country groupings.