This visualization uses a stacked bar chart to show the population distribution across countries, broken down by the top five religions. The chart is generated with the Vega-Lite API, using `markBar()`, and encodes country on the x-axis, population on the y-axis, and religion as color. Data is fetched from a CSV file via `d3.csv` from a GitHub gist. The visualization is rendered with `vega.render()` and includes a tooltip for religion details.