A hierarchical tree visualization displays the countries of the world organized by continent and subregion, with the root node labeled "World." The visualization uses an SVG rendering approach, with the D3.js library's `tree` layout and `hierarchy` function to compute the node positions from the nested JSON data structure. The `linkHorizontal` path generator draws the connecting links between parent and child nodes, while text elements label each country and region. The data source is a static `data.json` file containing the nested geographic classification.