A world map rendered with D3's geoNaturalEarth1 projection and geoPath displays cities as semi-transparent circles sized by population via a square-root scale. The map includes graticules, landmasses, and country borders from the world-atlas TopoJSON dataset, transformed with topojson.feature and topojson.mesh. City coordinates and populations load from an external CSV, while React manages the SVG rendering. This example demonstrates combining geographic basemaps with proportional point symbols in a single React component.