Mühlhausen became a garrison town in the 19th century. A parade ground was laid out outside the town on Hollenbacher Landstraße. The so-called powder house, built in 1869/70, was used for the safe storage of ammunition for firing practice. The simple functional building was a single-storey building with a square footprint of 64 m2.

In September 1939, two families with a total of 12 people from the Saar region were forcibly admitted to this cramped and, at the time, completely run-down building with no water supply, no sanitary facilities and no interior furnishings. From October 31, 1939, a further 19 people from Uengsterode, district of Witzenhausen, were added. The following year, a large family from Mühlhausen also had to move here. In the most inhumane conditions, at least 48 men, women and children who had been disenfranchised as Sinti and Roma by the Nuremberg Race Laws were ghettoized in the powder house and in wagons they had brought with them.

In March 1943, they were deported to the Auschwitz extermination camp and other concentration camps. After liberation, the survivors of the Mühlhausen family were initially housed here again. In 1951, they were able to move into apartments in the town. The Pulverhäuschen was demolished in the same year.