This interactive histogram explores GDP per capita across countries and years using a React-based visualization built with D3 v5. A dropdown menu selects which country’s data to display, while a numeric input controls the number of bins in the histogram. The chart shows the distribution of GDP values as animated bars with tooltips revealing class ranges and counts. The visualization uses `d3.histogram`, `d3.scaleLinear`, and `d3.axisBottom`/`d3.axisLeft` to render SVG bars with transitions.