This example visualizes the hierarchical structure of world countries organized by continent and subregion, with a tree layout that branches from a global root. Built with D3 v5, it reads hierarchical data from a CSV file and renders it as an SVG using `d3.hierarchy`, `d3.tree`, and `d3.linkHorizontal` for smooth curved links. Pan and zoom functionality is enabled via `d3.zoom`, while text labels display country and region names at varying font sizes based on depth. The visualization uses a clean, minimal aesthetic with green connecting paths and serif typography.