 We explain how the tango started in the slums and went on to conquer the world. No doubt you've seen a tango in the movies or maybe even danced one yourself. These days, it's one of the most popular dances in the world celebrated for its fire and its passion. But where does the tango actually come from? The La Plata River is the natural border between Argentina and Uruguay. In the 19th century as part of a development program, immigrants flocked there from all different countries and cultures. They were hoping for work and prosperity, but for many of them, their dreams did not come true. Instead, they had to live with crime, prostitution and homesickness. So the people turned to music and dancing to distract them from their disappointment. In the music halls of the slums, African and South American styles blended together with European influences like the polka and the waltz. Slowly but surely, a new dance was born, that tango, soon to be accompanied by the distinctive sounds of the German bandoneon, an instrument similar to the accordion. During a tango, the dancers' torsos remain steady with the partners closely embracing. The woman feels the man's movements and follows them, taking steps that alternate between long and smooth and short and snappy. The dance expresses nostalgia and melancholy, colored by sensual passion. Since the many immigrants by the La Plata River included relatively few women, the men practiced dancing amongst themselves in order to impress the ladies later with their moves. The conservative upper class of the 19th century rejected the dance as wild and scandalous, but in France, it drew enthusiastic fans and before long, all of Paris was happily tangoing. In Europe, after the newly discovered style was adapted to be more socially acceptable, it soon spread quickly and enjoyed enormous popularity. Eventually, even the upper class got into it, and in the end, that tango became a standard dance around the world. Today, there are many variations of the tango, but they all share a common spirit of sensuality and passion.