This example shows a hierarchical tree of world countries arranged by continent and subregion, with each country name displayed in increasingly smaller text as the depth increases. The visualization uses D3 v5’s `tree` layout and `hierarchy` to structure the data, with `linkHorizontal` generating curved path links between nodes. Pan and zoom interactions are enabled via `d3.zoom`, and the SVG rendering applies a fixed stroke color for paths and a serif font with a text shadow for labels. The data comes from a nested JSON file containing geographic groupings.