This example renders a world map using D3’s `geoNaturalEarth1` projection and `geoPath` to draw land masses from TopoJSON data (countries-50m.json), with graticules and country borders overlaid. The map fills land with a teal color against a gray sphere, while interior boundaries appear as lighter strokes. Built with React for component structure, the visualization fetches the TopoJSON via `d3.json`, converts it using `topojson.feature` and `topojson.mesh`, and renders the final SVG paths.