This example presents a hierarchical tree of world countries organized by continent and subregion, rendered as an indented node-link diagram. The visualization uses the D3.js v5 library to parse a nested JSON structure, apply a tree layout, and draw the connections with horizontal link paths. Text labels display country names with depth-dependent font sizes, and the entire graph supports zoom and pan interactions via the `d3.zoom` module. The SVG output is styled with a custom serif font and a teal stroke for the linking paths.