This interactive stacked bar chart visualizes religious demographics across countries, showing population distributions by religion for nations like China, India, and the United States. The D3.js v7 visualization uses d3.stack to process CSV data into hierarchical series, with d3.scaleBand for x-axis positioning, d3.scaleLinear for y-axis scaling, and d3.scaleOrdinal for categorical color encoding. Built with React's useContainerDimensions hook for responsive sizing, the visualization renders SVG elements and supports click interactions that highlight the selected country with a black border stroke.