The ballroom style of Tango bears little resemblance to the original Argentine Tango from which it evolved.
Argentine Tango was introduced in Paris around 1912 and into New York soon after. Simplified and more 'socially acceptable' styles of the dance developed and became extremely popular across Europe and America through the late teens and early 20's.
The English (International) style came into being around 1922 and added simplified steps, sharper staccato movements and head snaps. This influence provided the distinct personality and characteristic appearance we recognize as Ballroom Tango today (e.g. as seen in movies such as 'Scent of a Woman' and 'True Lies').
Its sophisticated, tense and dramatic personality combined with its asymmetrical step patterns and powerful music have made this the 'Dancer's Dance' and an ongoing favourite.
Ballroom Tango is best danced to slow to medium tempo music with a constant, pronounced 8 count Tango rhythm (slow, slow, quick, quick, slow).