Over successive months, the ghetto’s borders were regularly changed, gradually reducing its area. Initially, the ghetto was bordered by Bagno, plac Grzybowski, Elektoralna, plac Bankowy, the Krasiński Gardens, Nowolipki, Świętojerska, Freta, Sapieżyńska, Konwiktorska, Stawki, Okopowa, Żelazna, Wronia, Waliców, Żelazna and Sienna. The area from plac Mirowski and part of ul. Chłodna served as an important communication route and was excluded from the ghetto. Prof. Jacek Leociak explains that “the paradox of the ghetto’s borders was based on the fact that they were supposed to be impenetrable and final – in the metaphysical sense of the word – they were intended to separate life from death. However, they changed. This involved the torture of people being forced to constantly move”. Over the period of German occupation, the system of determining the ghetto boundaries changed. Initially, the borders ran between properties. They were mostly invisible, because they were designated by the walls of pre-War buildings. Today we refer to them as just “walls" and not as walls in the “strict sense”. This means that, today, we will not find any relics of the ghetto wall if, using that concept, we understand it as a construction erected specifically to delimit the Aryan part of the city from the ghetto. In December 1941, the area of the ghetto west of ul. Żelazna, between ul. Leszno and ul. Grzybowska, was disconnected, thereby resulting in the ghetto being divided into two – the so-called “large” and “small” parts. At that time, the borders running between properties were moved to run along designated streets in order to control illegal trade – namely, smuggling. On 26th January 1942, a wooden bridge was opened over ulica Chłodna, at its intersection with ulica Żelazna, which connected both parts of the closed districts – the small and large ghettos.