Cuba became Latin America's most influential musical source as a result of Spanish colonisers' melodies blending with the polyrhythmic percussion brought over by hundreds of thousands of enslaved West Africans, whose rhythms launched a profusion of styles that continue to mutate and evolve. Legendary groups like Trio Matamoros introduced the call-and-response son montuno rhythm to urban audiences in the '40s, a meeting that eventually evolved into New York salsa. Mongo Santamaría mixed rustic rumba rhythms into jazz- and R&B-laced long-form grooves in the '60s, and Irakere concocted its own molten jazz-fusion sound during the '70s. Juan Formell combined 19th-century changüí with rock in his enormously successful group Los Van Van beginning in the '80s, while the pre-Revolutionary beauty of son, bolero, and danzón enjoyed yet another glorious heyday when the Buena Vista Social Club exploded in all its vintage glory in 1996.