I was searching for data and visualizations concerning magnetic indices like the aa index. I found links at NO AA ;).
That is the links to the Laplace Institute on that page are broken. Moreover searching on the website like via search or looking at the page
data sets didn't reveal anything. Googling revealed
those data files, but no visualisations.
For completeness I should mention that BGS holds also index data, but for the aa index they write

>the aa indices available on this service are not the definitive values (see note on compilation and changes) . Definitive aa are published by the International Service for Geomagnetic Indices (ISGI). Operated by LATMOS, France, ISGI, has an advisory board that is appointed by the Executive Committee of the International Association of Geomagnetism and Aeronomy (IAGA) and operates as part of the French BCMT (Bureau Central du Magn├ętisme Terrestre).