This example shows a hierarchical tree visualization of world geography, with nested groupings for continents, regions, and individual countries. The tree layout is rendered as an SVG graphic using D3.js v5, with the tree structure defined in a static JSON data file. The code loads the data with `d3.csv` for a separate building dataset, though the visible tree comes from the hierarchical JSON structure, and the visualization is sized dynamically to fill the browser viewport.