This example displays a world map with points representing cities, sized by population. The map is rendered as SVG using React, with D3's `geoNaturalEarth1` projection and `geoPath` drawing landmasses, graticules, and sphere outlines. City coordinates are projected onto the map, and circles are scaled with `scaleSqrt`. The code loads world topology from a JSON via `useWorldAtlas` and city data from a CSV using the `csv` utility, styling land areas and points with CSS.