Animated bar chart of historical and projected world population from 1950 to 2100, based on UN estimates. The chart displays bars for multiple regions, with a horizontal line marking the selected region’s population; hovering over a bar highlights it, dims others, and reveals percentage differences relative to the selected region. Built with D3 v5 using `d3.scaleBand`, `d3.scaleLinear`, `d3.axisBottom`, `d3.axisLeft`, and `d3.select` for SVG rendering. Data is melted from two CSV files via a custom `melt` function, loading UN population estimates and medium variant projections.