The first of the celebrated Solvay Conferences was an invitation-only conference, held at the Hotel Metropole in Brussels, Belgium, in the fall of 1911.
These conferences were named after Ernest Solvay, a successful Belgian industrialist and philanthropist, who founded an international school for physics and chemistry (as well as other important institutions).
While the most frequently described is the fifth conference (on Electrons and Photons), that took place in 1927, the photograph (Figure 1) of the participants in the first conference, on Radiation and the Quanta, is remarkable in its own right. Here are a few notable facts (clearly, some more important than others):
First, even though Ernest Solvay himself was not present when the photo was taken, his head (third from the left among the seated) was later pasted onto the photograph!
Second, of the 23 participants (other than Solvay), no fewer than nine won the Nobel Prize (one of them, Marie Curie, won it twice). Most of the others won other prestigious prizes, such as the Matteucci Medal, the RAS Gold Medal, the Smith's Prize, and more. The number of Nobel Laureates would have been even higher could four other original invitees (J. D. van der Waals, Lord Rayleigh, Joseph Larmor, Arthur Schuster) have attended. The first two of those won the Nobel Prize.
Third, there was only one woman in the group, Marie Skłodowska Curie. She was not only the first woman to win the Nobel Prize, but also the only woman to win it twice, the only person to win it in two different fields (physics and chemistry), and the first woman to be entombed in the Pantheon in Paris because of her own personal accomplishments.
Fourth, Albert Einstein was the second youngest participant in the conference. The youngest was British physicist Frederick Lindemann, who went on to become scientific adviser to Winston Churchill.
Finally, to end on an amusing note, you'll notice that with the exception of the British astrophysicist James Jeans, all the other men in the photograph wear mustaches!
Figure 1. Photograph of the participants in the First Solvay Conference.
Seated (L-R): W. Nernst, M. Brillouin, E. Solvay, H. Lorentz, E. Warburg, J. Perrin, W. Wien, M. Skłodowska-Curie, and H. Poincaré. Standing (L-R): R. Goldschmidt, M. Planck, H. Rubens, A. Sommerfeld, F. Lindemann, M. de Broglie, M. Knudsen, F. Hasenöhrl, G. Hostelet, E. Herzen, J. H. Jeans, E. Rutherford, H. Kamerlingh Onnes, A. Einstein and P. Langevin. Photograph is in the Public Domain.