This interactive multiline chart visualizes the GDP of 19 European countries from 2006 to 2023, using D3.js (v7.8.5) to render SVG line paths and an animated legend. Users toggle country visibility via checkboxes, with a tooltip displaying formatted GDP values. The data is fetched from a GitHub gist and parsed as CSV using `d3.csvParse`. A color scale from `d3.schemeCategory10` assigns distinct hues, and the chart includes dashed gridlines and an SVG-based legend for clarity.