This example shows a world map with country boundaries from the World Atlas TopoJSON dataset, where each country is color-coded and displays a tooltip with a numeric value on hover. The visualization uses D3 v5’s `geoNaturalEarth1` projection and `geoPath` to render the SVG paths, while `topojson.feature` converts the TopoJSON data into GeoJSON. A custom tooltip appears near the cursor using mouseover events and CSS positioning, and the `csv` data is matched to country IDs to populate the tooltip’s content.