diagonal: <zanzibar> thanks too!
Argentina really was a Great Chess Nation in the 20th century, when many players stayed in the country after the oubreak of WW II while the Chess Olympiad was held in Buenos Aires in 1939:
Both in terms of <player strength> (immensly during the Chess Olympiads in the 1950s) and in terms of <strong international tournaments> (especially in the cities of Buenos Aires and Mar del Plata), including FIDE Candidate matches, Fischer vs. Petrosian in 1971, and Korchnoi vs. Polugaevsky in 1980, plus another Chess Olympiad in Buenos Aires in 1978.
Those were the days: Buenos Aires <150th Anniversary May Revolution> in 1960, Korchnoi and Reshevsky won, contesting in the Aula Magna of the Faculty of Medicine, where Bobby Fischer, already a Candidate in the previous year, is doing unexpectedly bad, coming in below 50%, amongst others Szabo on third position, followed by shared fourth Rossetto (awarded the GM title), Guimard (awarded the GM title), Evans, and Taimanov, Olafsson, Unzicker, Gligoric, Benko, Uhlmann, Ivkov, Pachman, Wexler, Wade who beat Korchnoi, or legendary Eliskases. All-play-all with 20 players.
All-time leading players from Argentina (selection):
<Roberto Grau, Isaias Pleci, Damian Reca, then of course Miguel Najdorf (the Fangio of Chess), Herman Pilnik, Erich Eliskases, Jorge Pelikán, Carlos Skalicka, Movsas Feigins, Paul Michel (Pablo Michel), and other 'asilados', Julio Bolbochán, Héctor Rossetto, Carlos Guimard, Raúl Sanguineti, Alberto Foguelman, Bernardo Wexler (born in Bucharest, beating Fischer at Buenos Aires 1960), Óscar Panno (first Argentine born Grandmaster, World Junior Chess Champion in 1953), Miguel Quinteros (maybe the best-looking player in the 1970s and the last big name of an era), Carlos Bielicki (World Junior Chess Champion in 1959, retired soon from active chess, inactive), Pablo Zarnicki (World Junior Chess Champion in 1992, as third Argentinian chess player, inactive, apparently, he has moved on into more lucrative enterprises such as poker events), Gerardo Barbero (1961-2001), Jorge Szmetan (1950-2015), current: Carlos Garcia Palermo (settled to Italy. Garcia Palermo is the first and only Argentine player to have beat a reigning world chess champion, namely Karpov at Clarin in 1982, in classical chess), Daniel Campora, Pablo Ricardi, Pablo Lafuente, Rubén Felgaer, Diego Flores, and Sandro Mareco, the strongest Argentine player today>