The International Solvay Institutes for Physics and Chemistry in Brussels held the first world physics conference in 1911 and began to host them every three years. The most famous conference was the fifth conference on Electrons and Photons in 1927. Attendees included Marie Curie, Albert Einstein, Niels Bohr, and Werner Heisenberg, to name a few. Of the 29 attendees, 17 were current or future Nobel Prize winners.