This interactive world map displays country boundaries, graticules, and city populations using a natural Earth projection. Cities are rendered as semi-transparent circles whose radii scale with population using a square-root scale. Built with React and D3 v5, it loads geographic data from the World Atlas TopoJSON, processes it via `topojson.feature` and `topojson.mesh`, and draws the visualization as SVG using `d3.geoPath` and `d3.geoGraticule`.