Dariusz Piotrowicz, Kielce University of Technology Known, forgotten and unexplored city space – Sienkiewicz Street in Kielce Natural city development, regardless of its dynamics, makes progressive changes of the urban structure more or less noticeable. For the local society it is the function that usually determines the acceptance of the site. City squares, both historical and contemporary ones, always have an advantage over streets since their spatial value is more attractive. A square is said to be a living room of the city and a street – its corridor. However Sienkiewicz Street in Kielce challenges this view because in various media sources it is defined as the living room. It is the result of several factors, such as its central location, proximity of a railway line, modernization of the street and the change of its design, as well as its history. This article is devoted to the history of this Kielce street, its origins and development, and the process of shaping the inside. It describes the conditions which determined its public space as we know it. It portrays the already forgotten image which remains only in memory of the oldest Kielce citizens and is recorded in iconography. This article presents facts that so far have been known only to specialists and documents which have not been presented to the public yet. This way it introduces the known, forgotten and unexplored space of the street, giving answers to the questions of what, how and why. As a result it makes the meaning of the street in the urban structure of Kielce objective, leaving aside the users’ subjective experience of its space.