December 11 is National Tango Day in Argentina.  

Tango is one of the most influential and famous dances of the modern history, originating from the streets of 18th century Buenos Aires in Argentina and Montevideo in Uruguay as the favorite dance of the European immigrants, former slaves, working and lower classes of people. The quick rise in its popularity enabled this famous dance to quickly expand out of South America, becoming a commonplace in Europe, North America and the rest of the world. With the rich history, numerous types and styles, and incredible appeal, tango dance remains one of the most popular dances in the entire world.
History of Tango – Origin and Characteristics of Tango

Argentina issued this spectacular tango semi-postal stamp Aug. 26, 2019. It was part of a 9 stamp set 

This stamp was voted the most popular music related stamp of 2019 by the International Philatelic Music Study Group. And a well earned title for designer Evangelina Cinthia Raffaelli. Raffaelli has worked with Argentina’s postal design unit since 2013. 

December 11 was picked for National Tango Day because it was the birthdays of Argentina’s 2 most renowned dancers, Carlos Gardel and Julio de Caro.