This example renders a world map with circles sized proportionally to city populations, filtering for cities with over 50,000 residents. The visualization uses React to structure the SVG output, with D3 v5’s `geoAlbers` projection and `geoPath` for country boundaries, and a square-root scale for circle radii. Data comes from the Simplemaps World Cities Database, while country shapes use the World Atlas TopoJSON. The map also includes graticules and subtle styling for land and interior borders.