It remembers 17 October 1945, when a large labour demonstration at the Plaza de Mayo, in downtown Buenos Aires, demanded the liberation of Juan Domingo Perón, who was jailed in Martín García island.
On 10 October, upon Perón's leaving office as vice president, the CGT held a rally in his support in the corner of Peru and Alsina Streets, downtown.
On 11 October Ávalos took over as Minister of War, and that night a meeting was held at the Military Club (Paz Palace) with nearly 300 officers, among whom were about 20 of the Navy, to discuss the course to be followed, including as to whether to retain Farrell as president.
The assembly decided to send a delegation to meet with Ávalos and, indeed, the only points that had agreed was to request the immediate convocation of elections, the appointment of civilian ministers, lifting the siege and the arrest and prosecution of Perón.
Concurrently, a senior Senator from the Socialist Party of Argentina, Alfredo Palacios, obtained a Supreme Court ruling against the regime, and when the Paz Palace meeting ended at midnight, a presidential decree calling for elections was announced on the airwaves.
Historian Félix Luna wrote on the lack of realism that made this decision such a tactical mistake: While the army was divided into sectors that had serious disagreements, none of them could accept at that time give the government to recognize the Court as it involved a humiliating defeat.
On several occasions there had been clashes between elements Alliance and students, about nine o'clock that night without any clear explanation of its origin had a violent shootout between police and a group of protesters who threw the one person dead and more than fifty wounded.
Following the arrest, the newspaper Crítica (then the most widely circulated news daily in Argentina), announced on the front page that: Perón is no longer a threat to the country.
On Saturday, 13 October, Farrell met with the Attorney General, Dr. Juan Álvarez, and proposed to Ávalos that he form a new cabinet with the latter as a sort of Prime Minister, thus following a suggestion made to him by former Córdoba Province Governor Amadeo Sabattini.
The reason for the strike was expressed in a number of issues including freedom of political prisoners, calling for elections, maintaining the gains of workers, etc.. but, significantly, did not mention Perón.
Perón, citing health problems, managed to move him to a military hospital in the Belgrano district of Buenos Aires, where they arrive on the morning of 17 October.
The mobilization of workers began at dawn in the southern Buenos Aires neighborhoods of La Boca, Barracas, Parque Patricios, as well as in working class suburbs further south, such as Avellaneda, Berazategui, Lanús and Quilmes, as well as other, surrounding industrial areas.
Among the first to mobilize en masse were abattoir workers led by Cipriano Reyes in La Plata then home to numerous meat packing establishments, such as the important Swift-Armour plant.
They had a short meeting to agree on the conditions: Perón would speak to reassure the protesters, without making reference to his arrest, and persuade them to disperse; in return, the entire cabinet would resign, as would Ávalos.
At 10:30 pm that day, Dr. Juan Álvarez had attended Government House to deliver a letter with the names proposed for ministers together with the curriculum of them and their acceptance to the charges.
These included, Jorge Figueroa Alcorta, proposed for Minister Justice and Public Instruction, who had been involved in a 1942 plot with military cadets; Alberto Hueyo for the Treasury, who had been director of the CHADE electric utility when it fraudulently obtained an extension of its concession; Tomás Amadeo for Agriculture, was a close friend of U.S.
The mobilization of 17 October had two immediate effects: it forced Perón to return to the political struggle, and persuaded the Army to turning in his favor before those among the military leadership opposed to him could organize their colleagues against him.