The Old Prison Building was erected during the period 1906 to 1907 by the Works Division of the German colonial government of South West Africa under the management of the government architect-builder Gottlieb redecker. The building was used as a prison until 1963.
The unique character of the building lies in the fortress-like shape. Its two corner towers with their extensive stonework and intricate face-brickwork on the south-and north-western corners and an enclosed courtyard remind one of the military and jailing activities of the German colonial era. The foundation was made of stone in lime mortar, as are the outer and inner court walls.
The two towers contained a guardroom as wells as the prison kitchen with a storeroom. The original building, which included the two towers, consisted of two quarters for married wardens, two kitchens and a storeroom. The prisoners were housed in 35 single and 5 communal cells, a workshop cell, a hospital cell for sick prisoners, two cells for solitary confinement, and a laundry. All the cell doors opened onto a corridor on the inside of the outer walls, making escape practically impossible. As far as is known, there was only one successful escape in its entire history from 1907 to 1963.
By 1984, a six-storey office block had been erected on the site. The style was made to blend in with the restored prison building. One of the cells was purposefully retained in its original state in order to offer visitors an idea of the inside of the prison while it was still in use.
It is an A Class building with the score of 92 on the NIA Index. The building is situated between Robert Mugabe Avenue and Goethe Street in Windhoek, and was officially proclaimed a national monument on 1 April 1986.