This visualization displays global cities with populations over 50,000 as semi-transparent circles on a natural Earth projection. Circle radius encodes population magnitude using a square-root scale, making larger metropolitan areas visually prominent. The map renders country boundaries, graticules, and sphere outlines via d3.geoNaturalEarth1, d3.geoPath, and d3.geoGraticule, while React manages the SVG markup. City data originates from Simplemaps, loaded through d3.csv, and geographical boundaries come from World Atlas TopoJSON, processed with topojson.feature and topojson.mesh.