As a Brit I’ll take it as non English language films.
Not being Arty Farty but saw a B&W dubbed Russian version of Macbeth and it was incredible ,never really was into Shakespeare before that .
Apart from that the best films I’ve seen over the years ,The Battle of Algiers(French,NOT a documentry as so many people think)
Stalingrad(German)
R Point(Korean,watch it late at night ,on your own with the lights out)
My Top 10 foreign-language films (in chronological order):
Pandora’s Box (Pabst/Germany, 1928)
The Crime of Monsiuer Lange (Renoir/France, 1936)
The Seven Samurai (Kurosawa/Japan, 1954)
Ordet (Dreyer/Denmark, 1955)
La Dolce Vita (Fellini/Italy, 1960)
An Autumn Afternoon (Ozu/Japan, 1962)
The Battle of Algiers (Pontecorvo/Algeria, 1965)
Persona (Bergman/Sweden, 1966)
Chloe in the Afternoon (Rohmer/France, 1972)
The Spirit of the Beehive (Erice/Spain, 1973)
Whoops! Misread the thread title (plus, I’ve already posted here! :o). Still, they’re all great films—check 'em out! 
Un Chien Andalou An Andalusian Dog (Short 1929) - IMDb
I saw it in the '60s; not when it first came out. 
The Red Balloon (La Balloon rouge), which I think I saw on the CBS Children’s Film Festival, where foreign films were the norm.
Golly. I can’t remember the first subtitled film; Seven Samurai I’m guessing. But the first foreign films I saw were unabashedly English:
The Ladykillers and
Never Let Go
a double-bill at some arthouse my parents took me to when I was a kid (They loved Peter Sellers). When I looked up the latter on IMDb, I found the entry confusing. It says the US release date was 1963 but I swear I was younger, eleven perhaps, about two years before that date. Maybe the arthouse imported it special or something.