Officials, trade union representatives and citizens laid wreaths and placed flowers at the Polytechnic (now the National Technical University of Athens-N.T.U.A.) monument.
The three-day events will wind up on Saturday, November 17, with a march to the US embassy in Athens.
A three-day commemoration is held nationwide each year in tribute to a student uprising against the military dictatorship ruling Greece at the time, that was violently put down in the early hours of November 17, 1973 when the army and tanks were brought in to disperse the students that had taken over the Athens Polytechnic building and the civilians who had thronged to the site in support of the uprising.
The commemoration will once again take place under stringent security measures. The various departments of Athens University scattered throughout the Greek capital closed on Wednesday night and will remain closed throughout the three-day events.
The Polytechnic gates will open every morning and close at night during the three days, while teams of students, professors and N.T.U.A. workers will remain inside the Polytechnic campus to guard the premises.
Traffic restrictions have already gone into effect in the Polytechnic environs.
The organizers of the commemoration are mulling the holding of memorial events inside the campus in addition to the traditional exhibitions and speeches.
The commemoration of the Polytechnic uprising will be held on Friday in primary and secondary schools.