This visualization shows population projections by continent from 1950 to 2100, using a multi-line chart where each line represents a region. The lines are smoothed with a basis curve and blended together using a multiply effect. The code leverages d3.csv, d3.nest, d3.scaleTime, d3.scaleLinear, and d3.axisBottom/axisLeft, with data sourced from UN population estimates and medium-variant projections. A categorical color scale with a custom legend orders the regions by their final population values.