This example displays a natural Earth projection map with semi-transparent teal circles sized by each country’s 2018 population, drawn from UN population estimates and world atlas TopoJSON data. A square-root size scale encodes population values, with a corresponding size legend and an ordinal color legend for missing data. The visualization uses d3.geoPath and d3.geoNaturalEarth1 for map geometry, d3.geoCentroid to position circles, and d3.zoom for panning and zooming. Hovering a country reveals a tooltip with its region and formatted population.