Austria has been celebrating the 50th anniversary of the end of the Allied occupation after World War II.
Big crowds marked the day in front of Vienna's Belvedere Palace
Officials from Britain, France, the US and Russia - the four occupying powers - attended the event.
Russia has lent Austria the original copy of the State Treaty through which the country regained its sovereignty. It will soon go on display in Vienna.
Austria was first annexed by Adolf Hitler in 1938 and then occupied by the Allies for 10 years until 1955.
The ceremony was held at the Belvedere Palace, the imperial castle in Vienna where the State Treaty was signed on 15 May 1955.
The treaty established that Austria could not enter a military alliance nor allow any other power to set up military bases on its territory.
Any future union with Germany was ruled out, and it was denied the right to nuclear weapons.
Austrian President Heinz Fischer said: "You always have to deal with your past, and dealing with a complicated and brutal past, in particular with the time of the Nazi government, is always painful.
"On the other hand, I think we have reached clear conclusions, namely it is a fact that Austrians were not only victims in the Nazi time but also acting people. We have to confess this."
Chancellor Wolfgang Schuessel urged Austrians to value their freedom as "something incredibly precious".