O5

On the outside wall, to the right of the main entrance of St. Stephan's Cathedral, a small "O5" is chiseled into its dark grey stone and protected under hard clear plexiglass. It is a simple but powerful symbol for freedom in Austria.
"O5" has come to symbolize all of the Austrian resistance movements during the years dominated by the Nazi occupation, though originally it was adopted by the O5 Group in 1944.
In German, Österreich (Austria) is spelled with two small dots over the "O" called an Umlaut, which is a contraction of "Oe". The "5" represents the fifth letter of the alphabet "e". Thus, the "Oe" became "O5" as a shortened symbol for Austria's resistance movements. (The name Oesterreich was outlawed in the Third Reich and replaced by Ostmark.) As a symbol, "O5" connects Austrians of different religions, political beliefs, racial and ethnic backgrounds, and occupations, who struggled against national socialism.
Following the annexation of Austria in 1938, known as the Anschluss in German, and continuing until the end of the War in 1945, 2,700 Austrians were tried and executed for their resistance activities, 16,493 Austrian resistors were murdered in concentration camps, 9,687 Austrians were executed in Gestapo jails, 6,420 Austrians were killed in prisons and jails in German occupied territory, and 65,459 Austrian Jews were murdered in ghettos and camps. 130,000 Austrians fled because of their political beliefs as well as for their religious, ethnic, or racial backgrounds and hundreds of thousands were imprisoned.