This interactive stacked bar chart visualizes the estimated religious composition of the 20 most populous countries in 2010, with population in millions on the x-axis and country on the y-axis. Built with D3, the visualization uses an ordinal color scale mapping religions to distinct colors. Hovering over the legend highlights matching religions in the chart, while dimming others, making it easy to compare religious distributions across countries. The data comes from the Pew Research Global Religious Landscape report, and the chart includes a color legend with interactive hover effects.