This visualization displays the hierarchical structure of world countries, organized by continent and subregion, as a horizontal tree diagram. The data is loaded from a local JSON file and rendered as SVG using D3 v5. It uses `d3.tree` and `d3.hierarchy` to compute the layout, `d3.linkHorizontal` for the connecting paths, and a zoom behavior for panning and scaling. Node labels are positioned dynamically, with font size decreasing by depth, and text shadows improve readability.