This example displays world population data over time on a Natural Earth projection map, with countries colored by income group using a red sequential color scale. An animated color legend updates its categories and transitions, while a zoom interaction lets users pan and scale the map. The visualization uses D3 v5 with `geoPath`, `geoNaturalEarth1`, `scaleOrdinal`, `schemeReds`, `zoom`, and `transition`, loading data from a CSV and World Atlas TopoJSON files.