Officially the Avenida del Libertador General Bernardo O’Higgins, Santiago’s most vital east–west artery is universally known as the Alameda, a poplar-lined avenue used for strolling and recreation, and found in many Latin American cities. This one began life as La Cañada (or “channel”), when a branch of the Mapocho was sealed off shortly before independence, and a roadway was created over the old riverbed. A few years later, when the Supreme Director Bernardo O’Higgins decided that Santiago required an alameda, La Cañada was deemed the best place to put it: “There is no public boulevard where people may get together for honest relief and amusement during the resting hours, since the one known as Tajamar, because of its narrowness and irregularity, far from being cheerful, inspires sadness. La Cañada, because of its condition, extension, abundance of water and other circumstances, is the most apparent place for an alameda.” Three rows of poplars were promptly planted along each side, and the Alameda was born, soon to become the place to take the evening promenade.
Since those quieter times the boulevard has evolved into the city’s biggest, busiest, noisiest and most polluted thoroughfare. Still, it’s an unavoidable axis and you’ll probably spend a fair bit of time on it or under it: the main metro line runs beneath it, and some of Santiago’s most interesting landmarks stand along it.