This visualization displays population over time by region as multiple colored lines, using an ordinal color scale to distinguish each region. The chart orders the lines by their final population value, creating an intuitive ranking. It uses D3 v5 APIs including `nest()`, `scaleTime()`, `scaleLinear()`, `line()` with `curveBasis`, and `axisBottom`/`axisLeft`. Data is processed from UN population estimate CSVs, melted from wide to long format to generate the time-series paths.