What is the name of the first subway system in South America?

The first subway system in South America was the Buenos Aires Underground, opened in Argentina in 1913.

Its first section connected Plaza de Mayo with Plaza Miserere and is now part of Line A. The Anglo-Argentine Tramways Company built the line, which made Buenos Aires the first city in South America, Latin America, the Southern Hemisphere, and the Spanish-speaking world to operate an underground railway.

The original service was unusual by modern standards: it was conceived as an underground tramway, and its early cars had both low-level street doors and high-level platform doors. The line was built using the cut-and-cover method beneath major avenues, rather than bored deep tunnels.

A common mix-up is confusing the first subway line with the name of the entire system. Line A was the pioneering route; Buenos Aires Underground, locally called the Subte, is the network it belongs to. The system later expanded with lines B, C, D, E, and H.