A bar chart displays quarterly United States GDP growth from 1947 to 2015, with each bar’s height representing billions of dollars and hovering revealing a tooltip with the exact value. The visualization uses D3 v5 to load JSON data from FreeCodeCamp’s GitHub repository, scales the GDP values with `d3.scaleLinear`, and renders axis ticks via `d3.axisBottom` and `d3.axisLeft`. Bars are appended as SVG `rect` elements, animated through mouseover and mouseout transitions that show an overlay and tooltip.