A donut chart displays three categorical values—Country, City, and Continent—with proportional arcs colored via a categorical scale. A legend aligns beneath the chart, using text labels and colored rectangles. The code builds the visualization with d3.pie and d3.arc, and positions legend items by measuring each group’s bounding box width. The chart is rendered as SVG on an HTML page using React-style class syntax, with margins and a fixed outer size.