This visualization displays population trends over time for multiple global regions as distinct colored lines. A dark vertical marker indicates the currently selected year, which can be changed by moving the mouse across the chart, updating the selection dynamically. The chart uses D3.js v5 with SVG rendering, employing scales, axes, and line generators to plot the data. It loads UN population estimates and projections from CSV files, melts the data into a tidy format, and uses a color legend for region identification.