The Buenos Aires Underground (locally known as ''subte'', from ''"subterráneo"'' meaning underground or subway), is a high-yield system providing access to various parts of the city. Opened in 1913, it is the oldest underground system in the Southern Hemisphere and oldest in the Spanish-speaking world. The system has six underground lines and one overground line, named by letters (A to E, and H) and there are 100 stations, and  of route, including the Premetro line. An expansion program is underway to extend existing lines into the outer neighborhoods and add a new north-south line. Route length is expected to reach  by 2011.