This visualization combines a world map and a U.S. map in a single SVG canvas. The world map, using a Natural Earth projection, colors countries by population with a blue sequential scale, while the U.S. map uses an Albers USA projection to depict state-level crime rates in greens. Both maps rely on TopoJSON datasets loaded from `world-atlas` and `us-atlas`, rendered via `d3.geoPath`. The code builds color legends with `d3.scaleSequential` and tooltips for each geographic feature.