"Hasta la victoria siempre" was the signoff used by Ernesto "Ché" Guevara in the last letter he wrote to Fidel Castro.
It translates as "Forever, Until Victory" or in other words, "Keep fighting until victory". This was a reference to Cuba's continued resistance to America as well as Che Guevara's battle for liberation in Bolivia.
Shortly after writing the letter, Guevara was captured and executed by CIA Agent Félix Rodriguez. Rodriguez cut off one of Ché's hands as a souvenir, removed another finger which he promptly sent to Fidel Castro, and took Ché's watch which Rodriguez was still wearing and showing off decades later.