This area chart visualizes the world population from 1950 to 2015, sourced from the United Nations World Population Prospects 2017. The chart uses a smooth, curved area path to show population growth over time, with a red filled region and orange data points. The visualization is built with d3.v5, using `scaleTime` and `scaleLinear` for the axes, `area` with `curveBasis` for the area path, and `axisBottom` and `axisLeft` for the labeled axes. It also includes a custom tick format that converts values to billions.