What does viva la quinta brigada mean?

Answer 1

"Long live the fifth brigade", whatever that means.

Answer 2

"Long live the fith brigade"

You will also find the similar "viva la quince brigada"

"Long live the fithteenth brigade"

Both reference the fith international (or fitheenth overvall) brigade of the spanish anti-facists in the spanish civil war.

The international brigades were communist and anarchist foreign volunteers, who came to Spain to (eventually unsuccesfully) fight against the facist dictator Franko in the spanish civil war.

The term was popularized by the song of the same name.

The song has come to be used as a symbol for the struggle against facism and also for other international brigades (like the IFB and IRPGF, international brigades in the Syrian Civil war, who defend(ed) Rojava aka. "The democratic confedertion of Northern Syria" and it's anarchist/communalist ideals against the Islamic State, the turkish invasion and the Assads troops.)