Fashion is the style and custom prevalent at a given time. In its most common usage however, "fashion" describes the popular clothing style. Many fashions are popular in many cultures at any given time. Important is the idea that the course of design and fashion will change more rapidly than the culture as a whole. Fashion designers create and produce clothing articles. The terms "fashionable" and "unfashionable" were employed to describe whether someone or something fits in with the current or even not so current, popular mode of expression. However, more so in the modern era items termed 'not so current' may indeed fit into the term 'Retro.' Retro fashion allows rule shifts, such as 'old is suddenly new,' thus fashionable. The term "fashion" is frequently used in a positive sense, as a synonym for glamour, beauty and style. In this sense, fashions are a sort of communal art, through which a culture examines its notions of beauty and goodness. The term "fashion" is also sometimes used in a negative sense, as a synonym for fads and trends, and materialism. There exist a number of cities recognized as global fashion centers or fashion capitals. Fashion Weeks are held in these cities where designers exhibit their new clothing collections to audiences. The main five cities are Tokyo, London, Paris, Milan and New York - these five are renowned for their major influence on global fashion and are headquarters to the greatest fashion companies. Other cities, including Mumbai, Los Angeles, Seoul, Berlin, Rome, Osaka, Toronto, Hong Kong, Dubai, São Paulo, Sydney, Moscow, and Shanghai also hold fashion weeks and are better recognized every year.