The Obelisco is a symbol of Buenos Aires and National Historical Monument , inaugurated on May 23 rd of 1936. The 67mtrs hight structure was made to commemorate the fourth centenial of the first foundation of Buenos Aires . In its current place was the San Nicholas Church (Iglesia San Nicolás), and was no coincidence, because in its tower flamed , for the first time in the city, the National Flag, on August 23 rd of 1812.

It was projected by architect Alberto Prebisch and constructed by the company Siemens Bauunion, in 31 days (a record) by 157 workers, in its majority of European origin, saving the difficulties that meant the subterranean tunnels at that moment, by means of the construction of vaults in its foundation. Although it was resisted by the Buenos Aires population and was even considered the thought of demolishing it in 1939, today the Obelisco is Buenos Aires 's symbol, a point of contact and cheerful events.

According to its author, it adopted a geometric form, of Egyptian origin, because it's the form of traditional obeliscos.

This one is located in the Republic Square (Plaza de la República), that throughout history underwent several changes to facilitate the automobiles's transit.

* For its inauguration in 1936 its form was circular, coincident with the extension of Corrientes Avenue

* In 1962 the square became an ellipse of 200 meters (its biggest axis), to facilitate the peatonal crossing of the Avenue.

* In 1971, four lateral strips were opened, to let the vehicular transit flow

In 1987 the monument was surrounded by a grate that protects it from the graffittis

The inscriptions on the four faces of the Obelisco remember:

*that in that place the National flag was hoisted for the first time in the city in 1812,

* the two foundations of Buenos Aires (the ones of 1536 and 1580)

* and the designation of this city as a Federal District in 1880.

At first it was covered by calcárea rock of San Luis, but subway movements caused numerous loosenings. Because of that, it was painted with látex and, at the moment, its maintenance is made regularly.

On the inside, it is a hollow structure and the only way to get the top is by straight stairs, without railing, of 202 iron steps.

At one time, was thought to prepare its interior for a future tourist place, for that reason in each one of the seven rests that it has, there is an opening through which it would pass an elevator.

In the end, provided with lightning rods, there is a small room that is visited only by maintenance tasks.

There are two windows, each one of them has a metallic curtain and, by outside, a lamp that illuminates the end.

A peculiar fact, is the story of the appearance of an iron box, located in the inside part of the end, with a photo of the engine chief of the constructor company and its wife, along with a text directed to the one that demolishes the monument.