This stacked bar chart visualizes estimated religious demographics for the top 5 most populous countries in 2010, using data from the Pew Research Center. The visualization uses D3's SVG rendering and animation to display population figures by religion across China, India, USA, Indonesia, and Brazil. Each bar is segmented by religion, with a color legend for identification. The chart supports interactive exploration: hovering over a legend item highlights the corresponding religion across all countries by dimming the other bars, and tooltips show exact population values. Axes use a custom tick format converting billions to "B". The example is based on a Stacked-to-Grouped Bars block and incorporates tooltip logic from another block.