This bubble chart visualizes the correlation between average GDP and travel numbers across car makes, using circle size to represent highway MPG and color to distinguish brands. Built with D3 v7, it reads data from a CSV file and renders an interactive SVG with a tooltip. The example uses `d3.scaleLinear` for axes and bubble sizing, `d3.scaleOrdinal` with `d3.interpolateTurbo` for colors, and event handlers for mouseover interactions.