This area chart visualizes population trends across multiple countries over time, with each country represented by a filled area path. The data comes from a CSV file containing yearly population figures, processed into chronological series using d3.csv and custom data transformation. The visualization employs d3.area(), d3.scaleTime(), and d3.scaleLinear() for rendering, along with d3.axisBottom() and d3.axisLeft() for axes. A categorical color scale (d3.scaleOrdinal with schemeCategory10) distinguishes countries, while a legend identifies each series. The chart is rendered as SVG with configurable width, height, and margins through a reusable areaChart() function.