Find the most interesting dataset + visualize it

Find the most genuinely interesting REAL public dataset you can think of — then build a single self-contained HTML page that makes it explorable and self-explanatory: an interactive visualization a curious person could lose ten minutes in.

YOU pick the dataset, and the choice is part of the test — pick something surprising and meaningful, NOT 'iris', 'titanic', or 'gapminder'. Inline a representative sample of the data in the file; vanilla JS + inline SVG or <canvas>, no charting libraries. Include a short note on what the dataset is and why you chose it. Return only the HTML.