A narco-corrido (, Drug Ballad) is a subgenre of the Mexican norteño-corrido (northern ballad) music genre, a traditional folk music from northern Mexico, from which other several genres have evolved. This type of music is heard on both sides of the US–Mexican border. It uses a danceable, accordion-based polka as a rhythmic base. The first corridos that focus on drug smugglers—the narco comes from "narcotics"—have been dated by Juan Ramírez-Pimienta to the 1930s. Early corridos (non-narco) go back as far to the Mexican Revolution of 1910, telling the stories of revolutionary fighters. Music critics have also compared narcocorrido lyrics and style to gangster rap and mafioso rap.