This example visualizes active, recovered, and total COVID-19 cases across fifteen countries using overlapping horizontal bars. The visualization renders as an SVG via React, with red, blue, and green rectangles representing total vaccinations, total cases, and total tests respectively. It loads data from a remote CSV file using `d3.csv` and scales the bars with `d3.scaleBand` for the y-axis and `d3.scaleLinear` for the x-axis, while drawing gridlines and tick labels manually. The code leverages D3 v5 alongside React state and effects for data fetching.