This interactive bar chart visualizes the basic cost of Amazon services across fifteen U.S. cities, using horizontal bars to compare each city’s Total Library Size. Built with React and D3 v5, the app loads CSV data via `d3.csv`, then renders scales and axes with `scaleBand` and `scaleLinear`. SVG rectangles are generated declaratively through React’s JSX, while D3 utilities like `max` and `tick` formatting drive the axis layout. The visualization updates reactively when new data arrives, combining React’s state management with D3’s quantitative computation for a clean, responsive chart.