that before mod became commercialised, it was essentially an extension of the beatnik culture: "It comes from ‘modernist’, it was to do with modern jazz and to do with Sartre" and existentialism. Sparks argued that "Mod has been much misunderstood ... as this working-class, scooter-riding precursor of skinheads." Coffee bars were attractive to British youth because, in contrast to typical pubs, which closed at about 11pm, they were open until the early hours of the morning. Coffee bars had jukeboxes, which in some cases reserved space in the machines for the customers' own records. In the late 1950s, coffee bars were associated with jazz and blues, but in the early 1960s, they began playing more R&B music. Frith noted that although coffee bars were originally aimed at middle-class art school students, they began to facilitate an intermixing of youth from different backgrounds and classes. At these venues, which Frith called the "first sign of the youth movement", young people met collectors of R&B and blues records. As the mod subculture grew in London during the early-to-mid-1960s, tensions could arise between the mods, often riding highly decorated motor scooters, and their main rivals, the rockers, a British subculture who favoured rockabilly, early rock'n'roll, motorcycles and leather jackets, and considered the mods effeminate, because of their interest in fashion. Violent clashes could ensue between the two groups. This period was later immortalised by songwriter Pete Townshend, in the Who's 1973 concept album, Quadrophenia. However, after 1964, clashes between the two groups largely subsided, as mod expanded and came to be accepted by the larger youth generation throughout the UK as a symbol of all that was new. During this time London became a mecca for rock music, with popular bands such as the Who and Small Faces appealing to a largely mod audience, as well as the preponderance of hip fashions, in a period often referred to as Swinging London. Mid-late 1960s Swinging London As numerous British rock bands of the mid-1960s began to adopt a mod look and following, the scope of the subculture grew beyond its original confines and the focus began to change. By 1966, proletarian aspects of the scene in London had waned as fashion and pop-culture elements continued to grow, not only in England, but elsewhere. This period, portrayed by Alberto Sordi's film in Thank you very much, and in Michelangelo Antonioni's 1966 film Blowup, was typified