The music of Argentina includes a variety of traditional, classical and popular genres. One of the country's most significant cultural contributions is the tango, which originated in Buenos Aires and its surroundings during the end of the 19th century and underwent profound changes throughout the 20th century. Folk music was particularly popular during the 20th century, experiencing a "boom" in popularity during the 1950s and 1960s thanks to artists such as Atahualpa Yupanqui and Mercedes Sosa, prominent figures of the Nuevo cancionero movement. In the mid-to-late 1960s, the countercultural scene of Buenos Aires originated Argentine rock (known locally as rock nacional, Spanish for "national rock"), considered the earliest incarnation of Spanish-language rock for having an autochthonous identity that differed from that of England or the United States. It was widely embraced by the youth and since then has become part of the country's musical identity as much as traditional music. According to the Harvard Dictionary of Music, Argentina also "has one of the richest art music traditions and perhaps the most active contemporary musical life. Folk music Folk music—called música folklórica or folklore in Spanish, from the English folklore—comes in many forms, developed in different parts of Argentina with different European and indigenous influences. Among the first traditional folk groups to record extensively in Argentina, three of the most influential were from the northwest: Los Chalchaleros from the Province of Salta Los Fronterizos also from the Province of Salta and the Ábalos brothers from Santiago del Estero Province. Becoming nearly instant successes following their first albums around 1950, they inspired a revival of the genre in Argentina. The folklorists Sixto Palavecino, Jorge Cafrune, Facundo Cabral and the folkloric group known as Los Manseros Santiagueños, as well as Los Nocheros are included in the genre. Between 1960 and 1974, Leda Valladares created a documentary series, known as the Mapa musical argentino (Musical Map of Argentina), taping traditional folk music throughout the country. The recordings she made were funded by the National Endowment of the Arts and directed by Litto Nebbia for Melopea Records. A famous soloist in the genre is guitarist Eduardo Falú, known for the many compositions that set traditional poetry into music. Traditional folk music became increasingly important during the protest movement against the military dictatorship and the community divisions of the 1970s, with artists like Mercedes Sosa and Atahualpa Yupanqui, contributing to the development of nueva canción. Soledad