A React and D3.js starter renders a static world map using SVG. The map draws country boundaries from the World Atlas TopoJSON dataset, projected with `d3.geoNaturalEarth1` and converted to SVG paths via `d3.geoPath`. Countries appear as light blue shapes with black strokes. A separate React component, created with `createRoot` and `useRef`, displays a "Hello D3 & React" message, demonstrating integration between the two frameworks.