The Hungarian Revolution of 1956 was a spontaneous nationwide revolt against the Neo-Stalinist government of Hungary and its Soviet-imposed policies, lasting from 23 October until 10 November 1956. It began as a student demonstration which attracted thousands as it marched through central Budapest to the Parliament building. The revolt spread quickly across Hungary, and the government fell. Thousands organized into militias, battling the State police force and Soviet troops. The new government formally disbanded the State police force, declared its intention to withdraw from the Warsaw Pact and pledged to re-establish free elections. On 4 November, a large Soviet force invaded Budapest using artillery and air strikes, killing thousands of civilians. Organized resistance ceased by 10 November 1956, and mass arrests began. An estimated 200,000 Hungarians fled as refugees. By January 1957 the new Soviet-installed government had suppressed all public opposition. Soviet actions alienated many Western Marxists, yet strengthened Soviet control over Eastern Europe, cultivating the perception that communism was both irreversible and monolithic. Public discussion about this revolution was suppressed in Hungary for over 30 years, but since the thaw of the 1980s it has been a subject of intense study and debate.