Day of struggle for freedom and democracy - This day commemorates the student demonstrations that took place on 17 November 1989 in the Czech Republic, primarily on Wenceslas Square in Prague, during which students expressed their opposition to the communist regime. This day is considered to be the beginning of the so-called Velvet Revolution, a period of political change that led to the creation of two independent states, the Czech Republic and the Slovak Republic. The students chose the date of the demonstration not by chance, referring to the events of autumn 1939; on October 28 of that year, Prague students organized a demonstration to commemorate the 21st anniversary of the creation of Czechoslovakia (the state was officially established on October 28, 1918) in order to express their opposition to the German occupation. The Germans opened fire on the protesters, which resulted in the death of a medical student, Jan Opletal. His funeral, which took place on November 15, turned into a large patriotic demonstration. However, the SS broke up the march and made numerous arrests, and Czech universities were closed. It was in reference to these events that on 17 November 1989, Czech students (mainly in Prague) took to the streets to protest against the totalitarian regime.  

source: wyszehrad.com