This example displays a world map with circles sized and colored according to the number of cultural heritage objects associated with each country. The code uses `d3.geoMercator` for projection, `d3.geoPath` to render country boundaries, and `d3.scaleSqrt` for circle radii based on data from a SPARQL query. Hovering enlarges a circle and shows a tooltip with the country name and object count, while a dropdown filters by material category. A legend and zoom functionality are also included.