Looking for all the world like little kids at recess, two of the twentieth century’s greatest physicists (both won the Nobel Prize) watch a spinning tippy-top in fascination during a break at the 1954 inauguration of the Institute of Physics, Lund, Sweden. Wolfgang Pauli (1900–1958), on the left, was a deep mathematical theoretician, while Niels Bohr (1885–1962) was more of an intuitionist, yet the physics of the everyday schoolyard top straddled the purely mathematical and the experimental to embrace the imaginations of both men. Photograph courtesy of the AIP Emilio Segrè Visual Archives, the Margrethe Bohr Collection.