Tango is a partner dance that originated in the 1880s along the River Plate, the natural border between Argentina and Uruguay, and soon spread to the rest of the world.
Early tango was known as tango criollo (Creole tango). Today, many forms of tango exist. Popularly[clarification needed] and among tango dancing circles,[who?] the authentic tango is considered to be the one closest to the form originally danced in Argentina and Uruguay.
On August 31, 2009, UNESCO approved a joint proposal by Argentina and Uruguay to include the tango in the UNESCO Intangible Cultural Heritage.