"Tango", the music and lyrics (often sung in a form of slang called "lunfardo"), is Argentina's musical symbol. The Milonga dance was a predecessor, slowly evolving into modern "tango". By the 1930s, tango had changed from a dance-focused music to one of lyric and poetry, with singers such as Carlos Gardel, Hugo del Carril, Roberto Goyeneche, Raúl Lavié, Tita Merello, and Edmundo Rivero. The golden age of tango (1930 to mid-1950s) mirrored that of jazz and swing in the United States, featuring large orchestral groups too, like the bands of Osvaldo Pugliese, Aníbal Troilo, Francisco Canaro, Julio de Caro, and Juan d'Arienzo. Incorporating acoustic music and later, synthesizers into the genre after 1955, "bandoneón" virtuoso Astor Piazzolla popularized "new tango" creating a more subtle, intellectual and listener-oriented trend. Today, tango enjoys worldwide popularity; ever-evolving, "neo-tango" is a global phenomenon with renowned groups like Tanghetto, Bajofondo, and the Gotan Project.