Tango is a style of ballroom dance music in 2/4 or 4/4 time that originated among European immigrant populations of Argentina and Uruguay (collectively, the "Rioplatenses"). It is traditionally played by a sextet, known as the orquesta típica, which includes two violins, piano, double bass, and two bandoneóns. Earlier forms of this ensemble sometimes included flute, clarinet and guitar. Tango may be purely instrumental or may include a vocalist. Tango is well-known across much of the world, along with the associated tango dance.