Mercat de Santa Caterina is roofed with 325,000 hand-made ceramic hexagons in sixty-seven colours, laid in a wave that rises and drops across the whole building. From the doors you cannot see any of it. The roof only reads from a balcony or from the far side of the avenue, and from there the pattern turns out to be a spilled heap of fruit and vegetables. Enric Miralles and Benedetta Tagliabue designed it, and the tiles were fired at Granollers, each one fourteen and a half centimetres across.
It went on in 2005, a hundred and sixty years after the hall underneath opened as the first covered market in Barcelona. Rebuilding opened the ground: a Dominican convent stood here from the thirteenth century until crowds burnt it in 1835, and its foundations are now kept visible at the back of the hall. The trade is ordinary, and that is the point — fishmongers, butchers, a queue of people buying dinner. Mornings from Monday to Saturday are the market; arrive in the late afternoon and you get a remarkable roof over a hall of closed shutters.