This example shows a GapMinder-style visualization comparing GDP per capita and average lifespan across countries from 1800 to 2008. A scatter plot on the left displays country-level data points, while a line chart on the right traces each country’s lifespan trajectory over time, with a brushable slider and continent filter. Hovering over a point highlights its corresponding line and shows a tooltip with population, income, and life expectancy. The visualization uses D3 v6 with custom scales, SVG rendering, and animation transitions to update positions smoothly. Annotations display historical facts for specific years, such as the Spanish Flu pandemic.