This visualization shows the distribution of yearly infection counts across US states from 1970 to 1980, using a histogram. The code loads CSV data from a GitHub gist, computes bins with `d3.histogram`, and renders rectangles with `d3.scaleLinear` for axes. Hovering over a bar reveals a tooltip with the bin range and count. The SVG chart displays maroon bars that turn crimson on interaction, with clear axis labels and a title.