This visualization shows projected population over time by region, with multiple colored lines representing different areas. The line paths are sorted by their final population values, and a categorical color legend identifies each region. The code uses D3 v5’s `nest`, `line`, `scaleTime`, `scaleLinear`, and `scaleOrdinal` APIs. Data is loaded from UN population CSV files and melted from wide to long format in `loadAndProcessData.js`, then rendered as an SVG with axis labels and a legend.