A music festival is a community event with performances of singing and instrument playing that is often presented with a theme such as musical genre (e.g., rock, blues, folk, jazz, classical music), nationality, locality of musicians, or holiday. Music festivals are generally organized by individuals or organizations within networks of music production, typically music scenes, the music industries, or institutions of music education. Music festivals are commonly held outdoors, with tents or roofed temporary stages for the performers. Often music festivals host other attractions such as food and merchandise vending, dance, crafts, performance art, and social or cultural activities. Many festivals are annual, or repeat at some other interval, while some are held only once. Some festivals are organized as for-profit concerts and others are benefits for a specific charitable cause. At music festivals associated with charitable causes, there may be information about social or political issues. The Pythian Games at Delphi included musical performances, and may be one of the earliest festivals known. During the Middle Ages, festivals were often held as competitions. The music festival emerged in England in the 18th century as an extension of urban concert life into a form of seasonal cultural festivity structured around a schedule of music performances or concerts. Music festivals generally feature regular and extensive programming than more spontaneous or improvised forms of music festivity. In traditional genres such as folk and classical music, a music festival can be defined as a community event with performances of singing and instrument playing that is often presented with a theme such as musical genre (e.g., blues, folk, jazz, classical music), nationality, locality of musicians, or holiday. Music festivals have developed as an emerging industry which contributes to many national economies. For example, Coachella Valley Music and Arts Festival earned $114.6 million in 2017.