Population over Time by Region
The visualization comprises a line chart and a pie chart showing population trends over time by region, sourced from UN population estimates. The line chart displays population changes from 1950 to 2100, with each region colored distinctively, and includes a vertical line marking a selected year. The pie chart shows the population distribution for that selected year. Hovering over the line chart updates the selection, which synchronizes both charts. The implementation uses D3 v5 with `scaleTime`, `scaleLinear`, `scaleOrdinal`, `axisBottom`, `axisLeft`, `line`, `curveBasis`, `nest`, and custom `colorLegend` and `PieChart` modules, rendering as SVG.