This visualization shows the total sales volume of BMW vehicles over time across six world regions, mapped to representative countries, using a multi-line chart where each line tracks one country’s annual sales. The color of each line encodes the country’s overall sales classification—deep blue for the highest total, light blue for the lowest, and sea blue for intermediate values—while clicking a line highlights it with a black border. Built with D3 v7, the chart aggregates the supplied CSV data using `d3.rollups` and `d3.sum`, renders as SVG with `d3.scaleBand` and `d3.scaleLinear` axes, and includes a hover tooltip for precise value inspection.