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

Context paragraphs:
Metrovías: 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.

Prague Metro: The Prague Metro (Czech: "Pražské metro" ) is the rapid transit network of Prague, Czech Republic.  Founded in 1974, the Prague Metro now comprises three lines (A, B and C), serving 61 stations (predominantly with island platform), and consists of a transit network 65.2 km long.  Prague Metro system served 589.2 million passengers in 2012 (about 1.6 million daily), making it the fifth busiest metro system in Europe.

Shanghai Metro: The Shanghai Metro is a rapid transit system in Shanghai, China, operating urban and suburban rail transit services to 13 of its 16 municipal districts (except Fengxian, Jinshan and Chongming) and to Huaqiao Town, Kunshan, Jiangsu Province.  Opening in 1993 with full-scale construction extending back to 1986, Shanghai Metro is the third oldest rapid transit system in China, after the Beijing Subway and the Tianjin Metro.  It has seen substantial growth, significantly during the years leading up to the 2010 Shanghai World Expo, and is still expanding, with its most recent expansions having opened in April 2016.  It is the largest component of the Shanghai metropolitan rail transit network, together with the Shanghai Maglev Train, the Zhangjiang Tram and the China Railway-operated commuter rail services to Jinshan and to Lingang New City in Pudong.  The metro system is also heavily tied with other forms of public transport in Shanghai.

São Paulo Metro: The São Paulo Metrô (Portuguese: "Metropolitano de São Paulo" ), commonly called the Metrô, is the main rapid transit system in the city of São Paulo and the largest in Brazil.  It is also the second largest system in South America and the third largest in Latin America, behind the Mexico City Metro and the Santiago Metro.  The five main lines in the metro system (Lines 1, 2, 3, 4 & 5) operate on 81.2 km of route, serving 69 stations.  A sixth line, Line 15, is a monorail line that partially opened for service in 2014.  In 2014, the four lines operated by CMSP (Lines 1, 2, 3 & 5) achieved an average weekday ridership of 3.09 million, and provided 895.6 million rides over the course of 2014; the entire Metro system served 1.098 billion passengers when Line 4 is included with the other four lines.

List of metro systems: This list of metro systems includes electrified rapid transit train systems worldwide.  In some cases, metro systems are referred to as "subways", "U-Bahns" or "undergrounds".  s of October 2014 , 157 cities in 55 countries around the world host the approximately 160 metro systems that are listed here.  The London Underground first opened as an "underground railway" in 1863 and its first electrified underground line opened in 1890, making it the world's first metro system.  The metro system with the longest route length is the Shanghai Metro; the busiest one is the Beijing Subway; and the one with the most stations is the New York City Subway.

Tbilisi Metro: The Tbilisi Metro (Georgian: თბილისის მეტროპოლიტენი ) is a rapid transit metro system in Tbilisi, Georgia.  Opened on 11 December 1966, it was the fourth Metro system in the former Soviet Union.  Like most ex-Soviet Metros, most of the stations are very deep and vividly decorated

Zhengzhou Metro: Zhengzhou Metro () is a rapid transit metro rail network serving urban and suburban districts of Zhengzhou municipality.  The plans of Zhengzhou Metro line 1 and Zhengzhou Metro line 2 were approved by National Development and Reform Commission (NDRC) in February 2009.  Construction of Line 1 started on 6 June 2009.  Line 2 started construction on 28 December 2010.  As planned, Line 1 commenced services on 26 December 2013 and Line 2 commenced services on 19 August 2016.  In January 12, 2017, the southern extension of Line 2 allows the system to serve the Xinzheng International Airport.  It is the first and currently the only metro system in the Henan Province.

Foshan Metro: Foshan Metro (; branded as FMetro) is the metro system of the city of Foshan in Guangdong Province of China.  It is operated by the state-owned Foshan Railway Investment Construction Group and partly by Guangzhou Metro Corporation and is the tenth metro system to be built in mainland China.  Construction began in 2002 and the first line opened on 3 November 2010.  The metro system has two new lines and one extension under construction.

Metrorail (Miami-Dade County): Metrorail, colloquially called the Metro, is the heavy rail rapid transit system of Miami and Miami-Dade County, Florida.  Metrorail is operated by Miami-Dade Transit (MDT), a departmental agency of Miami-Dade County.  Opened in 1984, it is Florida's only rapid transit metro system, and is currently composed of two lines of 23 stations on 24.4 mi of standard gauge track.

Buenos Aires Underground: 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.

Supporting paragraphs: Metrovías Buenos Aires Underground
Answer: 1913