This interactive stacked bar chart displays the estimated religious composition of the world’s 20 most populous countries in 2010, based on Pew Research data. Each bar segment represents a religion’s population in millions, with total bar length showing overall country population. Hovering over the legend highlights the corresponding religion across all countries while fading others. The visualization uses `d3.scaleOrdinal` for color mapping, the `stack` function from `d3-shape` to compute stacked segments, and `@curran/responsive-axes` for axis rendering.