This example shows a choropleth world map colored by estimated population, sourced from World Atlas data loaded via `d3.json` and `d3.tsv`. A linear color scale maps population values from blue to dark blue, while hovering highlights individual countries. The map is rendered with `d3.geoMercator` and `d3.geoPath`, using TopoJSON features converted with the `feature` function, and the visualization updates responsively to the window size.