Johann Stojka, known to his family and friends as Mongo, was born on 20 May 1929 in Guntramsdorf, near Vienna.
Mongo and his family lived in Paletzgasse 42, Vienna, from 1939.
On 3 March 1943, Mongo was detained in Rossauerlände detention centre in Vienna.
Towards the end of 1943, Mongo was sent to Auschwitz-Birkenau Concentration and Death Camp.
Mongo was deported from Auschwitz-Birkenau to Buchenwald Concentration Camp in August or September 1943.
In early April 1945, Mongo was sent to Flossenbürg Concentration Camp.
Mongo was liberated by the American army near Rötz, Germany, in April 1945.
Mongo was finally reunited with his family in Hohenauergasse, Vienna, in May 1947.
Towards the end of 1947, Mongo settled with his family in Gymnasiumstrasse, Vienna.