This example displays city populations as scaled dots on a world map, using a square-root size scale to encode population values. The map is rendered with a D3 geoEqualEarth projection and geoPath, drawing land masses, graticules, and the sphere. Data comes from a CSV of world cities, fetched via D3’s `csv` method, while geographic topology is loaded as JSON and processed with TopoJSON’s `feature` and `mesh` functions. Circles are positioned by projecting each city’s latitude and longitude, with opacity set to 0.3 for a layered effect.