The Naujack Tenement House is one of the best-preserved elements of the former city housing development. This building, of Art Nouveau style, has some marvellous decorative elements on its façade and ornamental architectural solutions.

It was built at the end of the 19th century but its present shape dates from 1907. It was rebuilt into a little castle with small towers, has balconies on avant-corps and stained glass which has partially survived in its original form to the present day. Moreover, some elements of the original furnishing have survived as well, including, among others, a masonry heater and a coal stove. The renovation of the building was commissioned by Otto Naujack – an entrepreneur from Olsztyn, who bought the tenement house in 1896. As a result, on the façade of the building there was placed an inscription with his initials. These have survived until the present day as well.

Until WWII, the flats in the building were rented by rich tenants. Then, the building was taken over by the SS. Most probably, however, this saved the building from being destroyed. After 1945 it was the seat of public institutions. In 2008 a total renovation of the tenement house was finished and now it is the seat of the City Cultural Centre (Miejski Ośrodek Kultury).