This visualization displays the hierarchical structure of world countries, organized by continent and subregion, using a horizontal tree layout rendered as SVG. The code employs D3 v5’s `tree`, `hierarchy`, and `linkHorizontal` to compute positions and draw curved links, with each node labeled by its region or country name. Users can pan and zoom via `d3.zoom`, with font sizes scaling by node depth. Data comes from a static `data.json` file, and text styling uses the Playfair Display font with white shadows for legibility.