This example renders a world map using React and D3, displaying countries as filled polygons with black graticules and an amber sphere backdrop. It loads country boundaries from a world-atlas GeoJSON file and uses D3's `geoNaturalEarth1` projection and `geoPath` to convert geographic coordinates into SVG paths. The React component fetches data through a custom `useData` hook, then passes processed topology features and mesh interiors to the `Marks` component for rendering.