This example shows a tree diagram of the world’s regions, beginning with Asia and breaking down through subregions to individual countries. The visualization uses a horizontal link layout, with each country as a leaf node. It is rendered in SVG using D3.js v5, with the tree layout computed via `d3.tree` and `d3.hierarchy`. The links are drawn as horizontal paths using `d3.linkHorizontal`. The input data is loaded from a local JSON file.