Samba schools are musical and recreational associations linked to carnival, created in Rio de Janeiro between 1928 and 1932 approximately. The first competitive samba school parade was held during the 1932 carnival, and since then they have held annually, always during carnival. Samba schools were also created in São Paulo later in the 1930s and gradually spread throughout Brazil, expanding internationally from the 1970s onwards. Since the end of the 1950s, the samba school parade has been recognized as the principal event in the Rio de Janeiro carnival. It is characterized as a performance involving music, dance, costume, and artwork. In the 1930s, each school sang up to three different sambas: the rule of just a single samba per parade was established later. Instrumental accompaniment is produced by the bateria, a set of membranophones and idiophones, which is perhaps the most the most characteristic element of a samba school. In addition, a small group of guitars and cavaquinho (a type of ukulele) provide the harmonic base for the singing. A group of judges mark the competition: points are organized by theme, music, dance, and outstanding features. The parade has gone through numerous transformations over the years. One such was the growing importance of the enredo, the central theme or story guiding the parade as a whole. In the 1950s, the composition of the sambas for the parade came to be driven by the need to present each aspect of the enredo in the music and lyrics, which led to the creation of a new type of samba, the samba-enredo. At time, the sambas performed in the parades were not very different from the sambas released on records and sung in different contexts in festivities. In the 1960s, the coordination of all aspects of the parade, with the aim of showing the enredo in the best manner possible, led to the emergence of a new role, the carnavalesco, who is charged with choosing the theme and designing and planning everything related to the parade’s visual and scenic dimensions. Increasing public interest in the samba schools was accompanied by the growth of the parade itself, implying ever greater costs, connections, and conflicts with the public authorities and with different private economic agents, including in some cases illegal economic activities, such as gambling. The importance of the parade of the samba schools for the city of Rio de Janeiro was expressed in the construction in 1983–1984 of a new and immense urban structure, known as the Sambódromo. Designed to shelter the parades without disturbing urban circulation, as had happened until then in the mounting and dismantling of stands, the Sambódromo is used throughout the year. Its open spaces host various festive events in the city, while the closed ones are used for activities linked to public education.