Images from Wikimedia Commons, all in the public domain: Gauss at 1840: Christian Albrecht Jensen. Gauss at 1803: Johann Christian August Schwartz. Gauss's birthplace, photo by 1914. Gauss's diary: Göttinger Digitalisierungszentrum. Disquisitiones Arithmeticae, 1801. Giuseppe Piazzi: F. Bordiga. Sophie Germain: Berthe Chégaray. Gaussian heliotrope. Triangle network: Reinhold Gerstetter for the Deutsche Bundesbank. Theoria motus corporum coelestium, 1809. Wilhelm Weber: Rudolph Hoffmann. The images of the 10 mark note, the squaring of the circle, and the determinant and matrix notations are from Euler’s Eyes collection. The interactive figures were made for this website.