This stacked bar chart shows BMW sales volume by year, broken down across five regions (Asia, North America, Europe, South America, Middle East, and Africa), with regions color-coded and clickable to toggle their visibility by turning bars white. The visualization aggregates the CSV data using `d3.rollups` to sum `Sales_Volume` per year and region, then renders the result as stacked bars with `d3.stack`, scales via `d3.scaleBand` and `d3.scaleLinear`, and includes axes, grid lines, and an interactive legend for filtering regions.