Music — free, often outdoors and performed by anyone who so chooses: that is the concept behind the Fête de la Musique, an event that began in France and is now celebrated worldwide under the name World Music Day. Since 1982 the Fête de la Musique has taken place annually on June 21 in France, where free performances are organized (or simply materialize, impromptu) in parks, public squares and indoor venues and along city streets. The event has gradually grown abroad, thanks in part to local French consulates or cultural organizations, and in 2014 the day was celebrated in 120 countries and 700 cities — including an estimated 17,000 concerts in France alone.

Source: Yahoo Music
Link: World Music Day extends it reach to 100+ countries