This example shows a choropleth map of COVID-19 total cases across Sweden, Denmark, and Norway over time, with a slider to scrub through the available dates. The map uses SVG paths rendered with `d3.geoPath` and a Mercator projection fitted to geographic data from a world GeoJSON file. Each region’s fill color is driven by a `d3.scaleSequential` with `d3.interpolatePlasma`, mapping case counts from a CSV dataset. A tooltip is attached to the paths via mouse events, though it is referenced but not fully instantiated in the provided code, and the slider updates the displayed date label.