Tango: a sad thought that is danced

Tango summons a place and a time lost to us. It is a musical narrative of days long gone when tango belonged to compadritos, dark streets and whorehouses. Borges recounts in his History of the Tango (1955) how tango began in brothels as a dance of brave men, outlaws and thugs, who gamble on their lives and make bets with their knives.
You are listening to El Tango by Borges and Piazzolla. The complete poem, in Spanish, can be found here. I could, for the time being, only find the English translation of a part of the poem:

„Where could they be?“ asks the elegy
of those who have disappeared, as if there were
a zone in which Yesterday could be
Today, Still, and Yet.

Where, I repeat, is that underworld
that was created, in dusty dirt alleyways
or in lost villages,
by those who lived with knives and courage?

They are in the music, in the persistent
strumming of the guitar,
that narrates, through a gay milonga,
the innocent festival of courage.

That outburst, the tango, that devilry,
defies the busy years;
made of dust and time, men do not endure
as long as the light tune
that is simply time. The tango creates
a shady, unreal past that in some way is true,
an impossible memory of having died
fighting, on a corner in the slums.

It is this tango of knives and brothels that Borges longed for. This is also the tango imagined in his short story, Man on Pink Corner:
"... milonga ran like grass fire from one end of the room to the other. Francisco Real danced straight-faced, but without any daylight between him and her."