This example displays a choropleth map of Australia, showing state boundaries and labels with hover-based population tooltips. It uses a Mercator projection centered on the country via `d3.geoMercator()` and renders geographic features as SVG paths through `d3.geoPath()`. State polygons are styled with a light fill that darkens on mouseover. The map loads GeoJSON data from a remote gist, and labels are positioned using `path.centroid()`. A custom tooltip div reveals the population property for each state on hover.