This interactive stacked bar chart displays the religious composition of the top 20 most populous countries, with each bar segment representing a religion’s population in millions. Built with D3 7.8.5, it uses `scaleOrdinal` for color mapping and `scaleLinear` with `scaleBand` for axes. A hover interaction on the color legend adjusts segment opacity and highlights the selected religion across all bars. Data comes from a bundled CSV file, and the visualization resizes responsively to its container.