A horizontal bar chart displays population counts for Spanish provinces, with bars extending from left to right and province names listed vertically. The visualization loads population data from a TSV file and renders it using Observable Plot’s `Plot.barX` mark within a `Plot.plot` container. A custom `marginLeft` of 250 pixels accommodates the longer province labels. The code fetches the data with `d3.tsv` and `d3.autoType`, then appends the generated chart to a designated div element.