This interactive bar chart visualizes the religious composition of the 20 most populous countries, showing population sizes per religion. Each horizontal bar is segmented by religion and colored using a categorical scale. It uses D3.js (version 3.5.5) with SVG rendering, including axes, a color legend, and a tooltip via d3-tip. Hovering over legend entries highlights the corresponding segments in the foreground layer, while a semi-transparent overlay fades the remaining bars.