In many countries, Classic Canasta is still played in more or less its original form, sometimes alongside a number of variations. The rules were standardised in North America around 1950, and it was this version of the game, which will be called Classic Canasta on this page, that gained worldwide popularity. It was extremely fashionable in the 1950's, threatening for a while to displace Contract Bridge as the premier card game.
From there it spread to Argentina, the USA and throughout the world.
The game of Canasta is said to have originated in Montevideo, Uruguay in 1939 (see for example this archive copy of Philip E Orbanes' article The Canasta Story).