International Symposium on Algebraic
Topology, Mexico City, 1956.
Front row, from left
to right: 1. William Massey 2. (?), 3. Friedrich
Hirzebruch, 4. Hans Samelson, 5. Raoul Bott,
6. J. H. C. Whitehead.
Second row: 1. (?), 2. (?), 3. (?), 4. (?), 5. Witold
Hurewicz (who was killed a few days later falling
off a pyramid), 5. (?), 6. (?), 7. Solomon Lefschetz.
Third row:
1. (?), 2. (?),
3. Morris Hirsch, 4. (?), 5. (?), 6. (?), 7. Leopoldo Nachbin.
These identifications are according to Michael Atiyah, who may have been lecturing at the time the photo was taken.