The Austrian National Day is celebrated on October 26 and relates to political developments after WW II.
After the end of the War, Austria was occupied by the four Allied forces (Soviet Union, United States, Great Britain, and France), who divided the country into four zones. The capital Vienna was also divided in four, with the historic central district being jointly administered by the “Allied Control Council”. Although the Austrian parliament was democratically elected, every legislative regulation or political action of the government at first required consent by the Allied Control Council and later on could still be vetoed by it.
The negotiations over a State Treaty putting an end to the occupation could finally be concluded in the spring of 1955: the Austrian State Treaty was signed on 15 May 1955 in Vienna's Schloss Belvedere and entered into force on July 27, 1955.
As the last remaining foreign troops left Austrian territory on October 25th, October 26 was de facto the first day on which Austria had regained its status as an independent and sovereign state. Thus, the Austrian Parliament chose this very special day to pass the constitutional law on permanent neutrality to highlight the fact that it represented a unilateral and independent decision. Informally however, Austria's engagement to permanent neutrality was the motivation upon which the Soviet Union had agreed to the signing of the State Treaty and the withdrawal of her troops.
Every year, the Federal Government celebrates this day with a series of events in Vienna:
The Federal President and the Federal Minister of Defense attend a celebration at Heldenplatz.
The Federal President lays a wreath at the tomb of the Unknown Soldier at the Burgtor.
The Council of Ministers holds a festive meeting.
The Federal President addresses the population in a “State of the Union”-styled speech on TV.
The Federal Chancellery opens its doors to the public
The new recruits of the Austrian Armed Forces are sworn in.
The citizens have the possibility of visiting the federal museums for free on that day. Various institutions also open their doors to the public (ie. the Federal Chancellery). Austrian Embassies around the world celebrate the Austrian National Day by hosting a number of different events for Austrian citizens.