Ada Krystyna Willenberg, whose late husband, Samuel Willenberg, was one of the few uprising participants to survive Treblinka, appealed Thursday for a proper museum to be built at the former site of the Nazi German camp.

The current memorial to the 900,000 Jews who were killed at Treblinka between 1941 and 1944 is a symbolic graveyard with boulders bearing the names of places in Europe where the victims lived before they were sent to the camp in occupied Poland.

The Nazis operated multiple gas chambers at Treblinka, considered the deadliest Nazi camp after Auschwitz.

During the Aug. 2, 1943 revolt, prisoners took guns from a storeroom and attacked camp guards. About 300 inmates managed to escape, but fewer than 100 avoided being caught and survived.