This example maps world countries using the Natural Earth projection, rendering landmasses as black paths against a blue sphere. It loads GeoJSON data from the world-atlas TopoJSON file via `d3.json` and converts it with `topojson.feature`. The visualization uses `d3.geoNaturalEarth1` for projection and `d3.geoPath` to generate SVG path data, appending each country as a separate `<path>` element with the `country` class.