In which of these card games do players build on melds?

Canasta is a card game of the rummy family of games believed to be a variant of 500 Rum. Although many variations exist for two, three, five or six players, it is most commonly played by four in two partnerships with two standard decks of cards. Players attempt to make melds of seven cards of the same rank and "go out" by playing all cards in their hand.

In card games, a meld is a set of matching cards, typically three or more, that earn a player points and/or allow him to deplete his hand. Melds typically come in sequences of ascending cards belonging to the same suit known as runs (8♠ 9♠ 10♠) or sets/groups of cards of identical rank (8♠ 8♣ 8♥). Other ones may be marriage (e.g. K♥ and Q♥) and bezique (Q♠ and J♦).

Melding is typical in games of the Rummy family, such as Canasta and Gin. It is also used in other games such as mahjong. Melds are also made in some trick-taking games, such as Pinochle and Bezique.

The game of Canasta was devised by Segundo Santos and Alberto Serrato in Montevideo, Uruguay, in 1939. In the 1940s the game quickly spread in myriad variations to Chile, Peru, Brazil and Argentina, where its rules were further refined before being introduced to the United States in 1948.