The Banach–Tarski Paradox
Cut a solid ball into five pieces, move them around, and you have two balls the same size as the first. Nothing was stretched.
192423 min read
German mathematics
Felix Hausdorff
1868 – 1942
Founder of modern point-set topology and of measure and dimension theory. His 1914 paradoxical decomposition of the sphere minus a countable set is the direct ancestor of the Banach–Tarski theorem. Persecuted as a Jew under the Nazi regime and facing internment, he took his own life with his wife and her sister in Bonn in January 1942.