A world map is visualized as a hierarchical tree, with continents, sub-regions, and individual countries as nodes. The tree layout is computed using D3’s `tree` and `hierarchy` functions, and links are drawn with `linkHorizontal`. Node labels are positioned with scaled font sizes based on depth, and the SVG output is styled with a green link color and a serif font. The visualization supports pan and zoom via D3’s `zoom` event, with the data sourced from a JSON file.