This world map visualizes the number of universities in 24 countries, using a choropleth color scale from light to dark blue on a natural Earth projection. The D3.js v7 code loads country boundaries from a TopoJSON file via `d3.json`, converts them with `topojson.feature`, and renders them as SVG paths using `d3.geoPath`. A color scale is created with `d3.scaleSequential` and an `interpolateBlues` interpolator. Hovering over a country triggers a mousemove event that displays a tooltip showing the country name and its university count, with data sourced from a CSV file.