Tango is a social partner dance which originated in South America. In spite of its name, Uraguay and Chile also lay claim to originating it. Tango Argentino should not be confused with ballroom tango which is a sanitised version of the dance developed in Europe in the 1920s and 1930s because the Argentine brand was considered a little too steamy.
Salon tango (the most social version) is a fully improvised dance, though it clearly follows rules which give it its appearance. The leader, who is usually the man, expresses himself by interpreting the music in his own steps and those which he invites the follower, usually the woman, to make. Historically, there is an element of "showing off" the woman by making her dance well.
A show version of the dance has also been developed which is more likely to be choreographed and includes aspects of jazz and ballet dancing.
Socially, dancers also dance milonga and vals. Tango is danced in bars of two beats each but phrased in two lots of two bars, giving a phrase of 8 beats. Milonga is also in bars of two beats each, but phrased two bars at a time. Vals is in bars of 3 beats (though usually fast enough to be in 1), where the first beat of each bar "corresponds to a whole beat in tango".
Occasionally we dance canyengue, which is a particular style of tango with a slightly higher stepping characteristic (possibly due to its having been dance in the sawdust and blood on slaughterhouse floors).
Lately, we have held some classes in an Argentine folk dance called chacarera.