The Obelisco is the defining monument of Buenos Aires. It was inaugurated in 1936 to celebrate the 400th anniversary of the first, but unsuccessful, founding of the city by Pedro de Mendoza. (The city was later reestablished in 1580.) It sits at the intersection of Corrientes and Avenida 9 de Julio, the heart of the Theater District and the focal point of the vista from Plaza de Mayo through Diagonal Norte and along 9 de Julio. The monument sits in the oval Plaza de la República, once the site of Iglesia de San Nicolás, where the Argentine flag was first displayed on August 23, 1812, shortly after independence from Spain. This church was demolished, but an inscription on the north side of the Obelisco honors its noble sacrifice. Like the Eiffel Tower in Paris, the project was criticized by many when it was first built but has since been embraced by the city as its main symbol.
When Argentines have something to celebrate, the Obelisco is where they head. If you're in town when Argentina wins an international event, you can be sure that hundreds of people will gather around the Obelisco with flags in their hands, waving them at the cars that honk in celebration as they head past. The edges of the plaza have plaques that celebrate the various provinces that make up the country. Unfortunately, many had to be replaced with replicas when the plaza was renovated in 2007, since the originals were stolen for the value of their copper in the years following the 2001 peso crisis. The view from the Obelisco would undoubtedly be fantastic, but the structure was not built for this purpose. As the city's preeminent phallic symbol, it has occasionally been graced with a very large condom on December 1, International AIDS Awareness Day. Though this has not been done in years, postcards of this event are available at kiosks.