This stacked bar chart displays the estimated 2010 religious breakdown of the 20 most populous countries, using horizontal bars with each country’s total tests on the x-axis and location on the y-axis, colored by ISO code. The visualization uses D3 v3 with d3.layout.stack to compute layer offsets, d3.svg.axis for ticks, and d3.legend for a color legend. Hovering over a bar shows a tooltip via d3-tip, while hovering over the legend highlights only that religion’s bars by overlaying a semi-transparent rectangle. Data originates from Pew Research’s Global Religious Landscape, processed through a custom script.