This example shows a hierarchical tree diagram of geographic locations, with the world branching into USA, India, and South Korea, and further into individual states and cities. It uses D3.js v5’s `d3.tree` and `d3.hierarchy` to compute node positions, then renders the structure as an SVG. Node circles and connecting paths are colored according to the `type` and `level` properties in the dataset, with labels placed beside each circle.