In 2002 readers of voted Young's double-slit experiment with single electrons as "the most beautiful experiment in physics" of all time. Pier Giorgio Merli, Gian Franco Missiroli, and Giulio Pozzi carried out this experiment in a collaboration between the Italian Research Council and the University of Bologna almost three decades earlier. I examine their experiment, place it in historical context, and discuss its philosophical implications.

Vienna today is one of the capitals of research on foundations of quantum physics. We reconstruct the development of modern physics in Vienna, with a focus on foundations of quantum mechanics (FQM), which is a sub-field of quantum mechanics. We show that the influence of Erwin Schrödinger and, in more recent years, the initiatives of Anton Zeilinger-the two main intuitive reasons-cannot alone account for today's outstanding research landscape on FQM in Vienna. We highlight four additional factors that played a crucial role in the development of foundational research in Vienna: 1) the Viennese heritage of the cultural golden age just before World War II; 2) the long-lasting institutional connection between the faculty of physics and philosophy; 3) a rise of several initiatives that gave forum to the interplay of physics and philosophy; and 4) the influence of several external scholars in the Viennese scientific landscape. Our analysis is informed by interviews with the most pertinent scientists, a detailed survey of the relevant social networks, and review of the main primary literature.