This bar chart displays the top 20 countries by reported COVID-19 cases, using horizontal bars to compare values. The visualization loads CSV data via `d3.csv` and slices the first 20 rows, with React managing state and rendering SVG elements. Scales are created using `d3.scaleBand` for the y-axis and `d3.scaleLinear` for the x-axis, with axis ticks manually generated and mapped to React components. Each bar is drawn as a `rect` element, with the x-axis grid lines and tick labels rendered as SVG `line` and `text` elements.