Metro – Buenos Aires’ Metro system (known locally as the “Subte”—short for subterráneo) opened in 1913, and is the quickest & safe way to get around town. It has six lines (A, B, C, D, E and H). Four parallel lines run from downtown to the capital’s western and northern outskirts, while Línea C runs north–south and connects the two major train stations of Retiro and Constitución. Línea H runs from Once south to Av Caseros, with future expansion plans. The Subte shuts down at 11 pm and reopens at 5 am.
Fares range from $2.50 (for one ride) to $25 (for 10 rides), with discounts for students, teachers and the disabled.
Here is a map of Buenos Aires’ Subte train system: