This visualization displays a hierarchical tree of world countries, organized by continent and subregion, using a collapsible-free horizontal layout. The code builds the tree with `d3.tree` and `d3.hierarchy`, rendering links as horizontal paths via `d3.linkHorizontal`. Text labels scale in font size based on depth, and the entire view supports pan and zoom through `d3.zoom`. Data comes from a pre-structured `data.json` file, and the SVG is styled with custom CSS using the Playfair Display font.