This example displays a world map with countries rendered as interactive SVG paths that turn grey on hover. It loads GeoJSON data from the World Atlas TopoJSON file using d3.json, converts it to features with topojson.feature, and projects the map with d3.geoEqualEarth and d3.geoPath. The React component uses d3.fitSize to fit the map to a 960×500 viewport, while the useData hook asynchronously fetches and transforms the data.