This example demonstrates a bar chart built with D3 v6 and React, where each country from a CSV dataset is represented by a static rectangle. The code uses `d3.csv` to load and parse population data, converting the numeric values, then appends SVG `rect` elements via `selectAll().data().enter()`. The bars are fixed at 300 by 300 pixels, so the visualization shows the data structure rather than proportional sizes. The chart renders in an SVG container using declarative D3 selections.