Bésame mucho (various artists)
Written in 1940 by Mexican singer, Consuelito Vázquez, this is possibly the most covered Spanish language song—there is even a version done by The Beatles. This passionate song about the parting of two lovers is also recognized for its simplicity.
It should be worth remembering what Mexico was like when this song was recorded. When this song was released, it broke all the molds of convention. In the song, it is the woman asking her lover to kiss her passionately and the woman is the protagonist, since she is the one prompting the supposed departure.