This example demonstrates how to create a world map with D3.js, displaying country boundaries as green polygons on a blue spherical backdrop against a black ocean. The visualization loads geographic data from the World Atlas TopoJSON file via `d3.json`, then converts it into GeoJSON features using the `feature` method from TopoJSON. The map uses a Natural Earth projection (`geoNaturalEarth1`) and renders paths with `d3.geoPath`, while a separate path element draws the sphere outline. The SVG output highlights the simplicity of data-driven mapping.