A line chart displays projected population trends from 1950 to 2100 for major world regions, using data from UN population estimates. The visualization uses D3 v5 with React, rendering SVG paths via `d3.line` and `curveBasis`. Data is processed through a custom "melting" function that reshapes wide CSV data into tidy form, with `d3.nest` grouping by region and `d3.scaleOrdinal` assigning colors. A color legend is generated using a reusable `colorLegend` component.