This visualization presents the hierarchical structure of world countries, organized by continent and subregion, as an interactive tree diagram. It uses D3.js (v5) to process the JSON data with the `d3.hierarchy` and `d3.tree` layouts, rendering horizontal links via `d3.linkHorizontal` and text labels in SVG. The chart employs the `d3.zoom` API for panning and zooming, with node text sized inversely to depth.