This stacked bar chart displays the estimated religious composition of the 20 most populous countries in 2010, with each bar representing a country’s population in millions segmented by religion. Hovering over the legend highlights the corresponding religion across all countries while fading others. The visualization uses D3’s `scaleOrdinal`, `stack`, and `scaleBand`, with interactive legend handling via `mouseenter` and `mouseleave` events. Data comes from a Pew Research report on the global religious landscape.