On May 15, 1955, the Austrian Independence Treaty was signed in Vienna at the Schloss Belvedere among the Allied occupying powers (France, the United Kingdom, the United States, and the Soviet Union) and the Austrian government. It re-established Austria as a sovereign state. It officially came into force on July 27, 1955.
Leopold Figl was an important figure in this treaty. Although he resigned as Chancellor on November 26, 1953, He remained in the government as foreign minister. His appearance on the balcony of the Belvedere Palace waving the signed paper and speaking the words Österreich ist frei! ("Austria is free!"), has become an icon in the Austrian national remembrance.
As a result of the treaty, the Allies left Austrian territory on October 25, 1955. October 26 was celebrated as a national holiday since then. It is sometimes thought to commemorate the withdrawal of Allied troops, but in fact celebrates Austria's Declaration of Neutrality, it was done by the Austrian Parliament to affirm the country permanently neutral. It was enacted today, 56 years ago as a constitutional act of parliament, as part of the Constitution of Austria.
Today, Google doodle honors Austria's National Holiday, already three years in a row. This year's image includes the colors of the Austrian flag scribbled as google and an Austrian snow-laden mountain behind. I can't tell which but it's surely one which skiers and snowboarders frequent. (Unterberg?)