“Por una cabeza”, meaning “by a head [of a horse]” in Spanish, is the most famous and popular tango song by Carlos Gardel (composer) and Alfredo Le Pera (lyricist), written in 1935.
The tango has been performed by numerous tango orchestras and is commonly featured in films and television, most notably The Tango Project (Nonesuch Records), consisting of Accordionist William Schimmel, Pianist Michael Sahl and Violinist Stan Kurtis. Tango scenes with “Por una cabeza” appear in Planet 51, Schindler’s List, Scent of a Woman, Delicatessen, True Lies, All the King’s Men, Bad Santa, Episode 37 of Nip/Tuck, Episode 9 of Sweet Spy, the beginning and ending credits of I’m Sorry, I Love You, and the CSI: NY episode “Down the Rabbit Hole”, and in the movie “Frida” (Salma Hayek), Gardel is heard on a radio singing it. It is also quoted in David Del Tredici’s “Good News! Nilda is Back” (from the song cycle Miz Inez Sez). In Scent of a Woman, The Tango Project actually appears in the famous Tango scene starring Al Pacino. (Via)
This tune always sets me on a dreamy state. And with that I bid adieu.