This visualization uses a natural Earth projection to display global population estimates for 2018, with countries colored to indicate data presence or absence. Circles sized by population are plotted at country centroids using a square-root scale, with a legend showing the population scale. The code leverages D3 modules including `geoPath`, `geoNaturalEarth1`, `geoCentroid`, `scaleSqrt`, and `zoom` for interactivity. Data comes from a UN population estimates CSV and a TopoJSON world atlas, processed via `topojson.feature`.