This choropleth map visualizes world population by country using a natural Earth projection. It colors each country with a sequential YlGnBu color scale, where darker shades indicate higher population values, and provides a legend showing the population scale. The visualization uses D3's `d3.geoNaturalEarth1` projection and `d3.geoPath` to render countries from TopoJSON data, while population CSV values are mapped to each country's numeric ID. Interactive tooltips display country names and population totals on hover, built with D3 event handlers and an HTML overlay.