This example visualizes global population data for 2018 by coloring countries on a natural Earth projection map, with missing data highlighted in red. It uses D3 v5's `geoNaturalEarth1` and `geoPath` to render the map, `scaleSqrt` for proportional sizing, and `scaleOrdinal` with `schemeSpectral` for color encoding. The visualization supports zooming via `d3.zoom`, and tooltips appear on hover showing region names and population counts. Data comes from a CSV joined with TopoJSON world atlas geometry, loaded through `Promise.all` and processed with `topojson.feature`.