Warsaw Mayor Rafal Trzaskowski said more than 100,000 people were in attendance, while protest organizers put the figure at 150,000.
Police detained 37 people Friday evening, the vast majority of whom were football hooligans, Sylwester Marczak, spokesman for the Warsaw Police headquarters, said Saturday morning. Taking into account the huge number of participants, it was a “very peaceful” protest, he added.
Demonstrations of this scale were last seen in the Solidarity movement of the 1980s in Poland which led to the collapse of the government, analysts say.