A world map colored by GDP per capita displays each country’s economic standing for a selected year, controlled by a slider. Hovering over a country updates a line plot showing that nation’s GDP trend over time, with red and green reference lines marking the current year’s value. The visualization combines a `d3.geoEqualEarth` projection rendered as SVG with `d3.scaleLinear` color encoding, alongside a linked line chart built using `d3.line` and axis components. GDP data originates from a CSV file, while country boundaries use a GeoJSON source.