Supermarkets: they are ubiquitous yet hard to define, lauded and vilified in roughly equal measures, and in many countries they have a huge influence on what we eat. Technological innovations, big social changes and new shopping habits have all shaped their development and today’s megastores are a far cry from their small-scale ancestors of the 1930s. And yet, some quirks of supermarket design remain constant: for instance, why are the eggs always so hard to locate in the stores?Iszi Lawrence navigates supermarket aisles with the help of historian and economist Marc Levinson; Aarti Krishnan, Lecturer in Sustainability at Manchester University; Simona Botti, professor of marketing at London Business School and Forum listeners from around the world.(Photo: A customer in a supermarket. Credit: Adene Sanchez/ Getty Images)