Mexico City's status as one of the world's top culinary capitals is often credited to the creative tasting menus and celebrity chef collaborations found in its upscale Roma Norte neighbourhood. But the flavours served on those affluent, tree-lined streets often begin their journey to the plate at dawn – in a sprawling, chaotic market in one of the city's poorest boroughs. @BBCNews has more Central de Abasto, the wholesale market roughly the size of New York City’s Central Park, that feeds Mexico City’s best restaurants: