A world map with city points sized by population. The visualization uses a natural Earth projection with graticules and land boundaries rendered as SVG paths. City populations are scaled using a square root scale, mapping to circle radii with a maximum of 15 pixels. The chart is built with React, D3 v5's `geoNaturalEarth1`, `geoPath`, and `geoGraticule`, and loads city data as CSV and world atlas topology JSON.