Nearly every Sunday during the winter of 1933 in Budapest, a small group of students would meet somewhere in the city at a park or cafe to discuss mathematics. The gathering typically included Paul Erdös (1913–1996), who was attending the University of Budapest, György (George) Szekeres, a recent chemical engineering graduate of the Technical University of Budapest, and another student, Esther Klein.
In addition to feeding their passion for mathematics, the students enjoyed exchanging personal gossip and talking politics. In a way, they had their own, informal university without walls, and they relished the chance to explore new ideas.