From left: Beno Eckmann, Peter Hilton, Jean-Pierre Serre, André Haefliger, 2007 in Zürich (90th birthday of Eckmann)
Gert-Martin Greuel, Copyright is MFO
CC BY-SA 2.0 de
Mathematisches Forschungsinstitut Oberwolfach, <a rel="nofollow" class="external free" href="https://opc.mfo.de/detail?photo_id=9798">https://opc.mfo.de/detail?photo_id=9798</a>