This visualization displays population trends over time for global regions, using multiple colored lines to compare regional growth from 1950 through 2100. The chart combines historical data from U.N. population estimates with medium-variant projections, melting the dataset to create one line per region. The code uses D3 v5 with `d3.nest`, `d3.line`, `d3.scaleTime`, and `d3.scaleOrdinal` with `schemeCategory10` colors, rendering as SVG paths with a custom color legend.