In Spanish:
Don Quijote, or more properly, El Ingenioso Hidalgo, Don Quijote de la Mancha, by Miguel de Cervantes Saavedra is considered the epitome of Spanish language literature. That should keep you busy for quite a while.
Fernando de Rojas
“Tragicomedia de Calixto y Melibea”, or “La Celestina”, as it’s more commonly known.
Some of the following are plays and some others are short stories, but it’s basically a good collection of “classics” I remember from grade school.
Juan Ruiz de Alarcón
- “La verdad sospechosa”
Leopoldo Alas “Clarín”
-La Regenta
Gustavo Adolfo Bécquer
-Leyendas
Mateo Alemán
-Guzmán de Alfarache
Calderón de la Barca
-El alcalde de Zalamea
-Los cabellos de Absalón
-El cordero de Isaías
-La dama duende
-El gran teatro del mundo
-Guárdate del agua mansa
-La hija del aire
-A María el corazón
-Triunfar muriendo
-La viña del Señor
-La vida es sueño
Miguel de Cervantes Saavedra
-La Galatea
Marqués de Santillana
-Marqués de Santillana
Francisco de Quevedo
-El Buscón
Tirso de Molina
-Don Gil de las calzas verdes
-El burlador de Sevilla
Lope de Vega
-La dama boba
-El caballero de Olmedo
-Fuenteovejuna
-Peribañez
You can find the full text of each of the above in this webpage, which includes hypertext annotations and notes. I haven’t read them all, but the webpage looks great.
Also, anything by García Lorca, IMHO.
As for Latin American authors, you could start with Gabriel García Marquez’s “Cien Años de Soledad”, a great novel in the Magical Realism style, also “El Laberinto de la Soledad” by Octavio Paz, which is a great essay on the condition of being Mexican. There are, of course, many more, but it’s a start.
Have fun.
Lothos