In Buenos Aires, the tango starts with a gesture that is almost imperceptible to the untrained eye.
At traditional "milongas," as tango social dances are known, men do not approach women and ask them to dance. Rather, the Argentines sit across the room and make eye contact. If the woman does not avert her eyes, the man nods slightly. If the woman nods back, then he approaches her and they move to the floor.
That initial gesture is known as "el arte de cabeceo," or "the art of the nod." This...Full Story