Question: Metrovías operates a transit metro system that first opened in which year ?

Related documents: [0]  [DOC] Metrovías S.A. is an Argentine privately owned company that operates the Buenos Aires Underground and the Metropolitan services of Urquiza Line. 90% of Metrovías' shares are held by Grupo Roggio. [END] 
[1]  [DOC] The Buenos Aires Underground (Spanish: "Subterráneo de Buenos Aires" ), locally known as Subte (] , from "subterráneo" – 'underground' or 'subterranean'), is a mass transit metro system that serves the area of the city of Buenos Aires, Argentina. The first section of this network (Plaza de Mayo-Plaza Miserere) opened in 1913, making it the 13th subway in the world, and first underground railway in Latin America, the Southern Hemisphere and the Spanish-speaking world, with the Madrid Metro opening five years later, in 1919. As of 2015, Buenos Aires is the only Argentine city with a metro system, but there is a proposal to build a metro in the city of Córdoba (the Córdoba Metro), while a proposal to build a metro in Rosario was shelved in favour of a tramway network. [END]  
Answer: 1913
1913