Tango grew out of the mixing of many cultures along the R铆o de la Plata in the 1880s. People had moved to the cities from Italy, Spain, Africa and from the countryside, and they brought their music with them. The music and steps blended together, and tango was the result. Both Montevideo and Buenos Aires can fairly claim it as their own.
The music sounds a bit melancholy and serious - it has a special instrument called the bandone贸n, which looks like a little square accordion. When the bandone贸n plays, the music can sound like it is breathing in and out. One of tango's most famous songs of all time, 'La Cumparsita', was written in Montevideo in 1916.
Tango is a 'social dance'. That means anyone can learn it - you don't have to be a professional dancer. In Montevideo there are special evenings called 'milongas', where dancers gather to dance with each other in caf茅s and dance halls. Children sometimes join in too, especially at family gatherings.
In 2009, UNESCO (a part of the United Nations) added tango to its list of important world cultural traditions. Both Uruguay and Argentina were named together - because the dance belongs to both. The world has agreed: tango belongs to everyone, but its home is the two cities on each side of the wide river.