This visualization displays population trends over time for various global regions, with each region rendered as a distinct colored line using a spline curve. The chart employs D3 v5’s scaleTime, scaleLinear, and scaleOrdinal APIs to map years, population values, and categorical colors, respectively. Data is sourced from UN population estimates and projections, melted into a long format for multiple lines. An interactive color legend, built with a custom `colorLegend` function, annotates each region’s line.