This interactive example lets users switch between a world map, US states, and US counties. The React component fetches TopoJSON data from the `world-atlas` and `us-atlas` CDNs, converts it to GeoJSON with `topojson.feature`, and renders SVG paths using `d3.geoPath` and either `d3.geoNaturalEarth1` or `d3.geoAlbersUsa` projections. Buttons toggle the active dataset and map type, with the SVG clearing and redrawing on each change.