This visualization displays a world map with the population of major cities represented by proportional circles. Circles are sized using a square root scale based on each city’s population, overlaid on a gray landmass with graticules and interior borders. Built with React and D3 v5, it uses `geoEqualEarth`, `geoPath`, and `geoGraticule` for the map projection, while city data comes from a CSV file and world geography from TopoJSON.