Oschersleben Castle

The castle was built as a lowland castle in the immediate vicinity of the Bode. It was provided with ramparts and moats. The earliest documented mention dates back to 1205, although the castle is likely to be older. In addition to a core castle, there was an outer bailey to the north, which was later used as a farm yard. In the second half of the 19th century the domain passed into private hands. In 1896 the castle was demolished except for a stair tower that has survived to this day and rebuilt as a storage facility. The material from the previous building was used again.
Source: Wikipedia
The buildings were renovated from 2011 and now house the district and city archives.

With so many windows, the building doesn't look like a castle at all.

The first documented mention of a castle dates back to 1205 and was owned by the bishops of Halberstadt. In 1896 the castle was demolished except for the stair tower, which has survived to this day. The material from the former castle was used to build the storehouse, which is still preserved today.