This interactive visualization displays the hierarchical structure of world countries, organized by continent and subregion. The tree layout uses horizontal links to connect parent nodes to their children, with text labels sized inversely to depth for readability. Built with D3 v5, the code employs `d3.tree` and `d3.hierarchy` to process the nested JSON data, while `d3.linkHorizontal` generates the curved paths and `d3.zoom` enables panning and scaling, rendering everything as SVG elements.