The Argentine Tango is a social dance and musical genre that originated in Buenos Aires, Argentina and moved to Uruguay, and later to the rest of the world.
There were many thousands of immigrants in the late 1800's/early 1900's lured to Argentina with the promise of jobs in the cattle and lumber industries. These included Italian, Portuguese, Slavic, and Western European peoples, mixed with populations of black slaves, South American indigenous people, Spanish people from the early conquest, and people from other South American and Caribbean countries who all brought with them their cultural history, music, and dance. The resulting melting pot created what we know today as Argentine Tango.
The Argentine Tango is danced in an embrace that can vary from very open, in which leader and follower connect at arms length, to very closed, in which the connection is chest-to-chest, or anywhere between.
The dance relies heavily on improvisation. There is no "basic step."
The follower will usually be led to alternate feet. The leader may freely step with his left foot when the follower steps with her left foot too