Avenida de Mayo

Avenida de Mayo was laid out where there had previously been no street. A thirty-meter-wide strip was cut through the middles of the blocks between Rivadavia Avenue and Hipólito Yrigoyen Street (formerly Victoria Street). It now connects Plaza de Mayo with the Palace of the Argentine National Congress, but it was originally intended to ease the route from the port to Once railway station: the building of the Palace of the Argentine National Congress at the western end did not yet exist. The avenue's name continued that of the square and recalled the May Revolution of eighteen ten.

The project was championed by Torcuato de Alvear, the first mayor of Buenos Aires after the city became the federal capital. He wanted a broad thoroughfare through the center, where narrow colonial streets could no longer handle traffic and were considered dangerous for the overcrowded city after the yellow fever epidemic.

In eighteen eighty-four, Alvear secured a law allowing real estate to be expropriated along the future route. The municipality lacked the money. Owners were offered tax breaks and an increase in the value of the remaining plot in exchange for giving up the necessary strip of land. The law also allowed the entire property to be taken: officials expected to sell the surplus land, now with frontage on the new boulevard, and use the difference to pay for construction.

At the intersection with Perú Street stood a property belonging to Isabel Francisca Armstrong de Elortondo. She was the wealthy widow of a major landowner; the property formed part of the family capital. The future avenue split her holding at Perú, numbers fourteen through eighteen, in two. Municipal lawyers demanded that she hand over the entire property, including the land not needed for the roadway. Elortondo refused.

At first, the federal court sided with the municipality. Elortondo appealed and took the dispute to the Supreme Court of Argentina. In eighteen eighty-eight, four judges to one ruled that only the part the street would actually occupy could be expropriated. For the first time in Argentine history, judges refused to apply a law because it contradicted the Constitution.

Elortondo gave up the thirty-meter strip but retained the rest of the land. Once the avenue was laid out, it gained a new frontage and rose sharply in value. The municipal commission had to negotiate with other owners under the same rules; some raised their prices, construction dragged on, and it stopped during the economic crisis of eighteen ninety. Alvear did not live to see the opening. The avenue was ceremonially opened on July ninth, eighteen ninety-four.

Elortondo's property on Perú Street no longer exists. Today, the roadway of Avenida de Mayo runs through the part of it that the court allowed to be expropriated.