Why is a soap bubble round, and what shape does a film take when it spans a twisted wire frame? For one week, the Museum Beispiel in Zurich fills its foyer with giant bubble stations, wire frames to dip yourself, and models of the minimal surfaces that mathematicians have studied since the nineteenth century.
Short demonstrations run every hour, and members of the local mathematics institute are on hand every afternoon to answer questions — from “why hexagons?” to the Double Bubble Theorem. No registration is needed; just walk in, dip a frame, and watch geometry do its work.