This example combines OpenLayers and D3 to create an interactive map with city data. The React component overlays D3-rendered circles, sized by death counts from a CSV dataset, onto an OpenLayers basemap using the Stamen toner-lite tiles. The map uses `ol.View` for panning and zooming, while `d3.geoNaturalEarth1` and `d3.geoPath` draw geographic features like land, graticules, and city points. The basemap is filtered with CSS to invert its colors and reduce opacity, producing a muted dark background.