This area chart visualizes world population by year from 1960 to 2015, using a smooth curved path to show growth over time. The visualization loads data from a CSV file via `d3.csv`, then renders an SVG path generated with `d3.area` and `curveBasis`. Axes are created using `d3.axisBottom` and `d3.axisLeft`, with scales from `d3.scaleTime` and `d3.scaleLinear`, and population values are formatted in billions using `d3.format`.