This visualization displays population trends over time for various global regions, with each region represented as a distinct colored line. The chart highlights how populations evolve from 1950 to 2100, combining historical estimates with medium-variant projections. The code uses d3.nest to group data by region, d3.line with curveBasis for smooth paths, and d3.scaleOrdinal with schemeCategory10 for colors. A custom colorLegend component renders the interactive legend, while data processing in loadAndProcessData.js melts the CSV dataset into a tidy format using d3.range and timeParse.