This example displays a world map with six circles positioned over specific countries, where each circle represents the number of students from that country and is sized proportionally. The visualization uses the Natural Earth projection via `d3.geoNaturalEarth1` and renders country boundaries with `d3.geoPath`, while loading geographic data from a TopoJSON source through the `topojson-client` library. Student data points are manually defined with country names, student counts, and coordinates, then projected and drawn as SVG circles with labels showing the country name and count.