This map visualizes global population distribution across cities, using circle size to represent relative population counts on an equal-area projection. Built with React and D3, the example loads world land geometries and city coordinates, then renders landmasses, graticules, and sphere boundaries via `d3.geoPath` and `d3.geoNaturalEarth1`. City data is fetched as CSV and processed with `d3.csv`, with circle radii scaled by the square root of population. The visualization uses SVG output, with styling defined in CSS for land, ocean, and city markers.