Mexico City's airport, Aeropuerto Internacional Benito Juárez (MEX), is the main gateway to the country. Many airlines fly nonstop between major U.S. cities and Mexico City. If you're taking a taxi, purchase your ticket at an official airport taxi counter marked transportación terrestre (ground transportation); never take a pirata taxi (unofficial drivers offering their services). Reaching the city center takes 20 minutes to an hour depending on traffic. Within Mexico City, buses are a cheap and convenient way to travel. Leaving the capital, ETN (Enlaces Terrestres Nacionales) serves cities to the west and northwest and ADO buses depart southeast. Buses depart from four outlying stations (terminales de autobuses): Terminal de Autobuses del Norte, going north; Terminal de Autobuses del Sur, going south; Terminal Terminal de Autobuses del Oriente, going east; and Terminal de Autobuses del Poniente, going west. It's usually impractical to rent a car for travel within Mexico City, though it may be a good option for trips outside of the city. Within the city, you can also get around by pesero (originally six-passenger sedans, now minibuses), which operate on a number of fixed routes and charge a flat rate, or the metro, which is incredibly cheap, but can be super busy at times. Simply do not hail taxis on the street under any circumstances. If you need a cab but don't speak the Spanish necessary to call one yourself, your best bet is to have a hotel concierge or waiter call you a sitio.